2
“Memorials of the Ability of Them All”

Introduction

In late ancient Rome, local senators set up portrait statues of emperors in the Roman Forum while senatorial portraits were heavily concentrated in the Forum of Trajan, since both spaces granted lasting political benefits to those depicted in the images.¹ By the late fourth century, the historian Ammianus Marcellinus spoofed aristocrats seeking excessively formal statues that seemed to express yearning for prestige rather than for senatorial virtue. Ammianus hints that Rome’s aristocrats unwittingly caused cultural stagnation, since statues potentially preserved elite social hierarchy for generations to come. “Some of these men eagerly strive for statues, thinking that by them they can be made immortal, as if they would gain a greater reward from senseless bronze images than from the consciousness of honorable and virtuous conduct.”² Such overwhelming concern for lasting fame at the expense of righteous pursuits in Ammianus’s account raises questions about political representations in urban public space and how the decoration of a city made the generations of aristocrats and rulers appear to be everlasting. The desire for persistence extended to emperors whose portrait statues dominated the civic areas of late antique cities. This essay examines the interplay of portraits representing rulers and the politics of city space by examining the imperial portraits inserted into the Roman Forum around 300 CE, when an innovative form of rulership inscribed a new cyclical pattern of imperial rule onto the main civic area of downtown Rome.

Public space played an important role in presenting the dynamics of elite status during the later Roman Empire. In his The Political Landscape, Adam T. Smith analyzes what he characterizes as “geopolitical landscapes” in which the author distinguishes between our modern historical accounts that chart the development of ancient societies and the brilliant use of cityscapes by premodern political authorities to shape audiences’ views of both space and time.³ Ancient cities, considered as “landscapes” in Smith’s account, provide material clues to both social control and political decisions, since the physical residue at a site retains the traces of a ruler’s decisions.⁴ With the phrase political landscapes, Smith sets forth an interest in popular perceptions of authority that explain the everyday workings of ideology as mapped onto cities.⁵ Specifically, Smith investigates the politicization of ancient landscapes, analyzing Mesoamerica, Mesopotamia, and Transcaucasia by looking at urban adaptations that resulted in altered temporal patterns. One of Smith’s important insights concerns the possibility that a governing power might have shaped the landscape indirectly, often without having demanded specific urban interventions.⁶ In other words, new political ideologies often suggested widespread public participation, resulting in material expressions that were not specifically intended by rulers to advance their agendas. Even though Smith does not specifically address Roman civilization, his concern for the ways authorities exploited perceptions of time to signal themes of territorial control sheds light on the late antique Mediterranean. The pages to follow assess how four co-reigning emperors, or Tetrarchs, transformed popular concepts of temporal patterns in downtown Rome through the outdoor displays of artworks depicting emperors.

During the last decade of the third century, the Tetrarchic emperors Diocletian and Maximian divided the empire in two and designated themselves as senior emperors, called augusti, each ruling over one of the two realms and each choosing a junior emperor as a caesar, or successor. This new system of governance by Tetrarchs expanded imperial authority and thereby interrupted the drive by senatorial aristocrats to regain power and prestige. After introducing a highly regulated scheme of joint rulership, the Tetrarchs arranged a group of statues in the Forum to illustrate their new system of imperial succession, effectively mapping concepts of periodic renewal onto urban public space.

Tetrarchic campaigns reshaped the Roman Forum. In specific, the late antique Forum displayed Tetrarchic authority using column monuments with inscriptions and sculptural reliefs presenting the political and ritual goals. The inscriptions that accompanied the column monuments and portraits of emperors in the Forum were intended to remain on view for generations and thus the epigraphic texts indicate that public areas were believed to promote political stability. The Tetrarchs, in a sense, politicized the landscape of Rome by featuring imperial monuments in the busiest areas of the city and by generating innovative ceremonial practices. Monuments honoring the Tetrarchs reconfigured the ways audiences perceived emperors in the city.

In the third century Rome underwent a tumultuous succession of short-lived emperors prior to the reign of Diocletian. The empire’s crisis during this period dispelled all illusions that either the social order or imperial governance could survive without profound structural reform. Diocletian reorganized the administration by dramatically expanding the number of prestigious offices in the empire. Many of the newly appointed officials came from outside the senatorial ranks, even though there was no intention of depriving Rome’s senatorial elite of their hold on esteemed positions. Instead, with the goal of eliminating the opportunities for potential rivals to gain power in the large provinces, the Tetrarchs divided the empire into smaller provinces governed by civilian “vicars.” Civilians replaced the military officers as those who collected taxes and paid soldiers, allowing Diocletian to prevent the commanders from instigating uprisings in the command of troops whose loyalty had been bought with the payouts.⁷ The Tetrarchic emperors, therefore, guaranteed the longevity of imperial rule by eliminating those conditions that had once fostered usurpation. An important political shift occurred in 293, when the senior emperors, Diocletian and Maximian, appointed their first two junior caesares, Galerius and Constantius Chlorus, with an elder ruler governing each half of the divided empire together with the chosen successor. Although the caesares were chosen by merit and the sons of rulers were ruled out as candidates for the imperial posts, the appointed junior successors acquired sacred power identified as that of either Jupiter or Hercules.⁸ The caesares and the augusti devoted energies to strengthen the imperial jubilee ceremonies that, while rooted in earlier precedents, were altered during the Tetrarchic age so as to coordinate the schedules of the anniversaries for all four emperors. By practicing the rites of renewal together during jubilees, all of the co-ruling Tetrarchs appeared unified and imperial succession took on an almost routine pattern in the ritual schedule for the anniversaries. The Tetrarchic ceremonies are examined here in order to understand how the installation of column monuments in the Roman Forum honoring Diocletian and Maximian articulated time’s renewal within city space.

The Tetrarchs primarily maintained control over the vast Roman Empire due to the movements of the necessarily itinerant rulers as they traveled to meet military challenges at territorial borders. Yet a significant feature of Tetrarchic policy was the shift of imperial residences away from Rome. After expanding the size of the imperial bureaucracy and increasing the number of provinces, the Tetrarchs instigated a growth in assemblies and rituals centered upon elite officeholders in all corners of the empire.

In late antiquity, the location of the Roman Forum, bounded by the Palatine Hill, the Capitoline Hill, and the Imperial Fora, ensured the zone’s purpose as a meeting place. The paved piazza at the center of the old precinct attracted large audiences who gathered there to hear speeches from the platforms known as the Rostra (figure 2.1: 1, 2). In Rome, a tribune, an outdoor stage for public oratory, was equipped with numerous prows of ships taken in naval battles so that these many prows, or Rostra, prompted Romans to identify the speaker’s platform as a Rostra. Only occasionally did imperial processions and formal addresses by emperors occur in the late antique Forum, since the fourth-century rulers resided outside of Rome for the most part. Given the rare appearances of emperors in Rome, statues of emperors acquired even greater significance. These artworks surrounded all the edges of the central piazza and some lined the main processional thoroughfare, the Via Sacra (figure 2.1: 8, 9). This display strategy can inferred from other locations, particularly the old forum of Cuicul (Djemila, Algeria).⁹

Figure 2.1. Plan of the Roman Forum: 1: western Rostra; 2: eastern Rostra; 3: Temple of the Deified Julius Caesar; 4: Curia Senatus (Senate House); 5: Arch of Septimius Severus; 6: Basilica Julia; 7: Basilica Aemilia; 8: Via Sacra; 9: central area of the Roman Forum; 10: Forum of Caesar; A: the so-called Rostra Vandalica; B: atrium in the senatorial complex; C: Secretarium Senatus. (Drawing D. Tyler Thayer)

Profound cultural shifts in Rome, encompassing administration, ceremonies, religion, and elite social structure, provide a context for understanding the monuments honoring Diocletian and Maximian in the Roman Forum. The first generation of Tetrarchs renovated many of the structures in the Forum in addition to fostering the creation of monuments presenting their new concept of eternal rule. In particular, the Tetrarchic decoration of the Forum supported the cycles of ritual celebrations that defined a persistent rhythm of imperial governance. Diocletian and Maximian renovated buildings in order to advertise their concept of reconstituted time, which remained influential well beyond the end of the first Tetrarchy in 305 when these two senior emperors retired.

Rhetoric and Renewal

The surviving panegyric texts praising the four imperial members of Diocletian’s Tetrarchy feature important concepts of renewed time. An oration read aloud at Trier in 297 to celebrate Constantius Chlorus, the caesar of the western empire, establishes a link between Tetrarchic rule and the natural sequence of the seasons. The unidentified panegyrist establishes a parallel between the four emperors and the four seasons. To argue for the relevance of the seasonal patterns to the significant temporal events celebrated by the two caesares, Constantius and his cohort Galerius, the author mentions that both celebrated the accession to imperial rule (dies imperii) on March 1, 293. The first day of March marked the traditional New Year’s day. Political events, thus, precisely coincided with seasonal cycles commencing in March, since imperial anniversaries occurred on the first day of spring. “O season, at which it is rightly believed that all things were born, since we now see everything made strong in the same season [spring]. O kalends of March, as once you marked the beginnings of the revolving years, so now you mark those of eternal emperors. How many ages, most invincible rulers, do you generate for yourselves and for the state by sharing the guardianship of your world?”¹⁰ Even if the Julian calendar, used in 297, featured the New Year of 1 January, celebrations known as natalis martis on 1 March continued during late antiquity and appointing the caesares on the March date imbued the moment of imperial accession with a potential for renewal.¹¹ A cycle of imperial celebrations merged the ritual acts of regeneration with the desire for a lasting form of rulership. Joint dates of accession such as the concurrent appointments of Constantius and Galerius pointed toward the perfect coordination among the Tetrarchs. In fact, the conceptual unity further required that each individual emperor issue laws in the name of all four.¹² The new concept of unity among jointly reigning emperors tied to the joint accession dates was intended to install a lasting group of rulers whose ranks could be refreshed with successive appointments.¹³ Finally, jubilees renewed the initial moment of accession, such as when Constantius and Galerius celebrated the five-year anniversary of joint rulership (quinquennalia) in 297.

The four Tetrarchic emperors jointly ruled a single empire; it was separated into distinct administrative sectors and yet these were unified by the conceptual harmony among the rulers. All four emperors were praised together in the panegyric delivered in 297 where the division of the world into four emerged from the natural appearance of four seasons and the four essential elements. Addressing Constantius directly, the orator states: “Indeed all the most important things depend upon and rejoice in the number of your divinity, for there are four elements and as many seasons of the year, a world divided fourfold by a double ocean, the lustra which return after four revolutions of the sky, the sun’s team of four horses, and Vesper and Lucifer added to the two lamps of the sky.”¹⁴ The references to the morning star, Lucifer, and the evening star, Vesper, allude to the daily cycle of celestial events. The two stars transported by the chariot pulling the sun across the sky set forth that the two caesares, Constantius and Galerius, experienced renewal on a daily basis by comparison to the rising sun. Natural groupings of four give the four Tetrarchs coherence when they follow the “four revolutions of the sky,” since the elements of air, earth, fire, and water total up to four and there are even the four land masses.¹⁵ Nature, thus, grants to the four emperors the semblance that they adhere to a divine order.¹⁶

To sort out the spheres of governance, Diocletian ruled in the east together with the caesar Galerius while in the west Maximian served as augustus with Constantius as caesar. Despite the territorial division, the emperors presented an image of the two divided realms operating as one. Their unity was entirely conceptual, not necessary based on blood ties. Indeed, Diocletian broke the chain of dynastic succession by denying the birthright of emperors’ sons to gain imperial positions and he appointed new caesars in 305 who were unrelated to the current members of the imperial college.¹⁷ Further, all four acquired the victory title earned by a single emperor.¹⁸ In 305 Diocletian and Maximian retired jointly, allowing their junior successors to receive promotions in unison. Even though the initial pair of senior rulers preferred joint retirements to coordinate the moment of accession for the next two, the Tetrarchic emperors, after attaining positions of power, did not select precise terms for the imperial offices. The clear priority was the semblance of togetherness among the rulers as projected in coins, inscriptions, and public monuments.¹⁹ As a result, the first generation of Tetrarchs regulated the cycle of time by orchestrating and celebrating joint appointments. But those who joined the imperial college were not dynasts. Objections from Constantius’s son Constantine and Maximian’s son Maxentius to their initial exclusion from the Tetrarchy caused them to dismantle the non-hereditary system. It fell apart in 306.

Diocletian and Maximian had attempted to prevent such a crisis by establishing a parallel between earthly governance and the heavenly order. During the first Tetrarchy, Diocletian adopted the pseudonym of Jupiter and Maximian named himself after Hercules in anticipation that the divine identities would remain permanent even as the particular imperial officeholders changed. In Tetrarchic politics, the emperors reinstated among mortals the system that had always operated under Jupiter and Hercules.²⁰ During the first Tetrarchy, the accomplishments of Maximian renewed the power of Diocletian in the official orations and this reciprocity ultimately restored authority to the immortals, Jupiter and Hercules.

None of the Tetrarchs resided in Rome, refusing to live in the traditional locus of power and thereby preventing one individual ruler from appearing as if he were holding the topmost position. Clearly, all of the emperors had to remain on the move to defend borders at the empire’s periphery and they shifted their residences accordingly.²¹ Yet, in deference to the local senatorial traditions in the ancient capital, the Tetrarchs did not advertise the demotion of Rome. No longer the sole residential capital of the empire, Rome benefited nonetheless from architectural projects with the structures built up or restored and with proper credit accorded to the current emperors. Thus, even as the Tetrarchic rulers pursued globalization that transferred power to other cities, the co-ruling emperors exploited building activities to announce the benefits of renewal in Rome.

In the texts of the panegyrics, the Tetrarchic ideal of renewal is shown to establish a parallel between the natural order of seasons, on the one hand, and patterns of earthly governance, on the other. Since the Tetrarchs postponed the rituals of triumph until they could be conducted in unison during imperial anniversaries, the cycle of jubilees became critical events in providing a fixed schedule for each duo or foursome of victors to celebrate together. This type of triumph, commemorated each decade, required new types of monuments for the Tetrarchic Roman Forum.

The Tetrarchic Roman Forum

The emperors Diocletian and Maximian resurrected the prestige of Rome by updating public space and sponsoring architectural reconstruction projects. Thanks to the Tetrarchic renovations of the preexisting Rostra originally installed under Augustus at the west end of the Forum square, the Tetrarchs strategically articulated that they had updated the early days of the principate. Diocletian and Maximian also set up a row of five freestanding columns to support statues on the western Rostra. By adding a second, matching Rostra at the east end of the Forum’s paved central area with its own five-column monument, the Tetrarchs paired the two statue groups as the backdrops for the imperial jubilees through which they regularized time (figure 2.1: 1, 2).

There was a pressing need to rebuild much of the Forum at the outset of the Tetrarchy.²² At the end of emperor Carinus’s reign in 283, a tragic fire damaged much of the Roman Forum. During the following decade, senatorial assemblies could not be held in the ruined Curia Julia. Also, judges could not preside over law courts in the devastated Basilica Julia and Basilica Aemilia. By 300 Diocletian and Maximian had repaired the Augustan Rostra, the Senate House (Curia Senatus), the Basilica Aemilia, and the Basilica Julia (figure 2.1).²³ There is evidence that the Tetrarchs expanded the Senate House by integrating the senatorial assembly hall into a complex featuring a courtyard and senatorial meeting rooms inserted into the narrow halls (tabernae) to the west of the Curia (figure 2.1: 4, B, C).²⁴ To supplement the senatorial compound, Diocletian and Maximian turned the Forum’s central area into a site for imperial messages by linking the Augustan Rostra at the piazza’s west end with the newly inserted Rostra at the eastern edge of the square (figure 2.1: 1, 2). Diocletian and Maximian used images to connect their political innovations with their architectural conservation projects. These ideological messages about synchronized rulership were reinforced in Tetrarchic oratory.

What were the ritual implications of architectural restoration that Diocletian and Maximian pursued in the Roman Forum? When activated during imperial ceremonies, the two Tetrarchic Rostra with towering columns holding up statues suggested that the monuments reinforced the cycle of rituals by symbolizing divine temporal patterns. The key Tetrarchic event in Rome was the twenty-year jubilee celebration in November 303 for which the augusti Diocletian and Maximian arrived in person. That ceremony also celebrated a jubilee for both caesares, Constantius and Galerius, who were acclaimed in absentia after they postponed by a year their tenth anniversary of rule. The Tetrarchic Rostra monuments featured statues referring to the unity among the four Tetrarchs. After all, the first generation of Tetrarchs rebuilt the Forum and thereby received honors for establishing the newly conceived empire. In sum, the Tetrarchs announced through the renewal of the Forum’s buildings that Rome had been fundamentally revived with the introduction of the rule by four emperors.²⁵

Diocletian and Maximian added meaning to their reconstruction projects by suggesting that they had reversed the degradation that had occurred over time. The fire of Carinus had probably eliminated most of the statues and inscribed statue bases that had appeared in the Forum prior to 283. As a result, statues honoring Tetrarchic emperors set forth new trends and, plausibly, new epigraphic habits. Inscriptions attest that portrait statues continued to be set up during the fourth and fifth centuries by senatorial patrons using such terms as reddere (“to restore; to give back”) and restituere (“to restore; to replace; to put in its former place”).²⁶ The terms used in the inscriptions connected physical restoration projects in the Forum with the wider accomplishments of Diocletian and Maximian. Clearly, the Tetrarchs linked architectural renewal with the empire that flourished once again. In fact, architectural conservation together with the affiliated displays of statuary provide a crucial lens through which to discern how the jointly ruling Tetrarchs pioneered a late antique manner of reinstating the past.

Remaking the Roman Forum’s Central Area

The buildings restored by Diocletian and Maximian brought new vitality to the Roman Forum together with defining the paved central area as a precinct for imperial messages framed by the two Rostra with their column monuments. The new Tetrarchic installation of a tribune, or speaker’s platform, at the east end of the Forum square replaced an old tribune once integrated into the Temple of the Deified Julius Caesar (figure 2.1, 2, 3).²⁷ Across the Forum square, the old western Rostra was widened by an addition so that it would correspond approximately to the width of the new eastern tribune (figure 2.1: A).²⁸

Diocletian and Maximian made the western Rostra into the platform holding Tetrarchic column monuments that supported statues alluding to the augusti and the caesares together with their divine namesake, an arrangement exemplified by the western tribune (Figure 2.2). It is appealing to consider the display at the western Rostra as framing a view toward the Temple of Jupiter Optimus Maximus on the Capitoline Hill for those standing in the Forum square. Facing in the opposite direction, audiences looking at the eastern Rostra saw columns rising above a platform through which they could observe the Temple of the Deified Julius Caesar. An explanation for arranging the two Rostra in this way is that together they demonstrated the concord among rulers while presenting an appearance that a pair of senior augusti and a pair of junior caesares on each monument operated as coordinated groups of four. Clearly, the column monuments emphasized Tetrarchic ideology. Indeed, the surviving inscriptions indicate that the two Rostra were the backdrops for jubilee rituals through which the imperial anniversaries were synchronized.

Figure 2.2. Reconstruction of the five-column monument on the western Rostra. (Drawing by D. Tyler Thayer)

Prior to Diocletian’s Tetrarchy, the Rostra had affirmed the imperial tradition without specific links to anniversary ceremonies. Julius Caesar started to transfer the speaker’s platform from the Comitium near the Senate House to the western edge of the Forum’s central area. Augustus than completed the project and added the other speaker’s platform emerging from the front of the Temple of the Deified Julius Caesar. The Forum square, bracketed at that time by the Rostra at the west end completed under Augustus and the other Rostra to the east honoring Julius Caesar, created a precinct that celebrated Augustus’s family ties to Caesar, his uncle and adoptive father.²⁹

Diocletian and Maximian celebrated the imperial past by reusing the Augustan Rostra. Their creation of a link between the widened western Rostra and the new eastern tribune drew upon the earlier affiliation between Augustus and Julius Caesar that had used the two older Rostra. This update to Augustus’s tribune identified Diocletian and Maximian as those who reinstated the revered Augustan age, now operating under the new Tetrarchic principles of collegial rule.

Tetrarchic Column Monuments

Only one base survives from the two Tetrarchic five-column monuments in the Roman Forum. This fragment of a column installation provides clear proof that the Tetrarchic monument was the backdrop for both victory celebrations and imperial anniversaries. On one side, the background features shields and pieces of armor arranged as markers of triumph with two kneeling figures in the center as conquered individuals, all referring to a military victory (figure 2.3: A). Also, two winged figures as personifications of Victory carry an oval shield featuring the inscription marking the imperial anniversary: “to the caesars, good fortune on the ten-year jubilee” (CAESARUM DECENNALIA FELICITER).³⁰ Given that the caesares Constantius and Galerius had postponed celebrations of their tenth anniversary to align with the twentieth jubilee of the augusti, the inscription plausibly commemorated the first two junior emperors of the Tetrarchy. Yet there is no mention of either emperor by name, an anomaly given the function of most inscriptions to honor individuals. By referring to the ten-year jubilee of unspecified caesares, this terminology allowed the five-column monument to commemorate any ruler with the title of caesar holding office for ten years. As a result, the installation at the Rostra looked forward to additional anniversary celebrations that were to extend into future generations.

Figure 2.3. Rome. “Decennalia” column base. A: inscribed face; B: relief with sacrifices at an altar; C: suovetaurelia relief; D: relief with procession. (Photos Gregor Kalas)

Another side of the Decennalia base shows an imperial figure, presumably one of the caesares, ritually sacrificing at an altar (figure 2.3: B). A relatively small winged Victory crowns the caesar as a youthful figure presents a box and another youth plays pipes nearby, while Mars stands to the left in a helmet. The personification of Roma is shown enthroned to the far right under the bust of Sol, the sun god, whose crown resembles rays of light.³¹ This image of the junior emperor presenting a ritual offering at the altar together with Mars, Roma, Sol, and Victory links the emperor’s triumph with the lasting favor of the deities. An additional sculptural relief on the base presents a pig, a sheep, and a bull—with sacrificial attendants behind them—as the animals destined for a specific sacrifice known as the suovetaurilia (figure 2.3: C). Offering the three animals was done to mark ritually the fulfillment of vows by caesares and augusti and to prepare for another ten years of rule.³² The carved column base features a final image of officials on a procession with four of them holding banners, presumably in honor of the four emperors (figure 2.3: D). Taken together, the reliefs on the plinth connect triumph, sacrifice, vows, and the simultaneous celebration of imperial anniversaries for all four rulers. The desire for persistence in Tetrarchic politics was expressed in the collegiality and synchronicity of jubilee celebrations. The reliefs reinforce the unity of the four rulers by suggesting that all four emperors received honors at once and by depicting the cyclical renewal that took place during jubilees.

Figure 2.4. Arch of Constantine, relief of Constantine and officials on the western Rostra with the five-column monument, Rome. (Photo Gregor Kalas)

A fourth-century relief from the Arch of Constantine records the enthroned imperial statues that were placed at the corners of the Rostra (figure 2.4).³³ The Constantinian relief further illustrates the imperial retinue addressing the public from a position on top of the platform, behind which appears a row of five columns supporting statues. Now-lost inscriptions from other column bases from the Rostra were rediscovered during the Renaissance. One commemorates a twenty-year anniversary and states, “to the augusti, good fortune on the twentieth jubilee”; the other was inscribed: “to the emperors on their twentieth jubilee.”³⁴ Taken together, all of the epigraphic testimony points out that the column bases marked the twentieth anniversary observed by Diocletian and Maximian in Rome on 20 November 303; as was the custom, the event came nineteen years after the date of accession. Ten-year celebrations for Constantius and Galerius, commemorated customarily at the end of the ninth year, were supposed to have occurred in 302, but their anniversary was indeed celebrated in 303. They did not physically arrive in Rome for the occasion. Schedules, nonetheless, were rearranged so as to unite the anniversaries of all four emperors and to strengthen the Tetrarchic ideology of synchronicity.³⁵ The manipulation of dates further implies that just as each individual Tetrarchic victory was shared by all four emperors, so did the entire college benefit from the commemoration of a jubilee earned by one or more of the group. This tradition was set in motion as soon as Diocletian appointed Maximian in 285; the former began his imperial reign in 284. Maximian was promoted to an augustus in 286, and both appointed the caesares to imperial posts in 293. The five-column monument attests that Maximian effectively altered the date of his accession to 284 while the caesares put off their anniversary for a year so that the celebration for all four occurred on the same day.

The five columns assembled at the western Rostra featured the unified college of Tetrarchic augusti and caesares. In the relief from the Arch of Constantine, a statue is shown to rest upon each of the five columns (figure 2.4). Visual distinctions between the central statue as shown in the relief and the four flanking representations prompted H. P. L’Orange to conclude that Jupiter’s image stood on the central column.³⁶ Since one of the now-lost plinths is documented as bearing the inscription mentioning the twenty-year jubilee of the emperors, VICENNALIA IMPERATORUM, the western Rostra installation must have commemorated all four emperors by retrospectively celebrating the twenty years of rule by the augusti while a vow was taken in anticipation of another twentieth jubilee to be celebrated in the future by the caesares.³⁷ Martina Jordan-Ruwe presents the argument that the statues representing the augusti were exhibited on the inner columns while statues of the caesares stood on the outermost columns.³⁸ The Tetrarchic column monument should be distinguished categorically from a triumphal arch such as the one commemorating Septimius Severus in that the platform provided the venue from which the emperor addressed the people and did not accommodate the movement through an arch of a triumph procession. The five-column monument, thus, focused on the imperial anniversary rituals more than military celebrations due to the emphasis on the peaceful succession of caesares who were slated to receive promotions as augusti after fulfilling their vows. Finally, the surviving inscriptions from the column bases disavow any signs that the monuments featured the names of emperors, perhaps as an indication that there were new identities for these Tetrarchic rulers, with each claiming to be an avatar of either Jupiter or Hercules.

Figure 2.5. So-called Rostra Vandalica, a late antique addition to the western Rostra in the Roman Forum, Rome. (Photo Gregor Kalas)

The architectural transformation of the western Rostra in the Roman Forum occurred for the optimal presentation of the columns. Patrizia Verduchi noted that the late antique modifications to the Augustan Rostra prove that the Tetrarchic columns stood directly on top of rather than behind the platform, as had previously been hypothesized.³⁹ The projection extending the Augustan Rostra slightly to the north widened this platform to accommodate a larger entourage of speakers and eventually the full width of the tribune was adorned with an inscribed text (figures 2.1: A and 2.5). Four inscribed fragments survive from a lengthy inscription for the Rostra. Christian Hülsen deemed the extension as the “Rostra Vandalica,” contending that the addition and the inscription both commemorated a victory over Vandals during the reign of emperors Leo and Anthemius (467–474).⁴⁰ Only one individual is specifically identified in the damaged inscription: Iunius Valentinus, an urban prefect who held this office at an unknown time, probably after 456.⁴¹ No specific reference is made to the victory over Vandals. Indeed, the widening needs to be dissociated from the installation of the inscription, since the inscribed blocks for the frieze were not restricted exclusively to the northern extension. In fact, the tribune’s addition was constructed prior to 334, because a Constantinian equestrian statue base produced in that year juts out on top of the base for the tribune extension and thus the equestrian monument was made after the addition to the Rostra (figure 2.6).⁴² Furthermore, the measurements of the inscribed blocks—whose lengths add up to almost 10 m across—extended approximately across the entire width of the Rostra.⁴³ The Tetrarchic construction of the second speakers’ platform on the east side of the Forum provides an interpretive context for the widened Augustan Rostra. It is likely that Diocletian and his colleagues ordered the lengthening of the western platform as an attempt to match roughly the dimensions of the corresponding Rostra set up on the opposite side of the Forum’s central area.

Figure 2.6. Equestrian statue base of Constantine overlapping the base of the western Rostra projection (the so-called Rostra Vandalica) in the Roman Forum, Rome. (Photo Gregor Kalas)

Diocletian and Maximian restored buildings in downtown Rome to reinforce the idea that they brought back the divine order of the gods, since they united the personae of the emperors with statues of divinities, probably Jupiter and Hercules, in the five-column monuments. Regionary catalogs identify three Rostra (rostra tria): the western Rostra, the Rostra in front of the Temple of the Deified Julius Caesar, and the eastern Rostra (figure 2.1: 2).⁴⁴ A surviving portion from the eastern Rostra rests upon the Forum pavement across from the northeast corner of the Basilica Julia. Additional remains from the eastern Rostra had been jettisoned by Pietro Rosa, director of the Forum’s excavations in 1872–1874.⁴⁵ The surviving structure retains the holes that had once received the ships’ prows. Evidence from the chronology of the brickwork together with testimony of a brick stamp identified as from the reign of Diocletian allowed Cairoli Fulvio Giuliani and Patrizia Verduchi to conclude that the Tetrarchs built the eastern Rostra.⁴⁶

Considered as a pair, the two five-column monuments anticipated repeated jubilee rituals after 303, each of which was intended to synchronize one team of Tetrarchic augusti with their appointed successors. The matched sets of Tetrarchic column monuments designated Rome as the stage for imperial anniversaries every ten years, which can be gleaned from the surviving inscriptions articulating the celebration of decennalia and vincennalia rites at the Rostra. Further, the Roman tribune monuments differ significantly from the isolated four-column monument honoring the Tetrarchs in Alexandria.⁴⁷ In Rome, the two sets of five-column monuments presumably did not identify the portraits in inscriptions; the surviving texts specifically omitted the emperors’ names. Thus, the pair of Tetrarchic Rostra in Rome articulated the hope for an everlasting set of transitions of future caesares to be promoted into positions as augusti. The near divination of each emperor allowed each to chart an imperial career path by means of the links to the gods; religious rituals confirmed authority while also aligning the joint anniversaries. Implicitly, senators of Rome were shut out of the process of affirming imperial appointments. Indeed, Diocletian, in violation of precedent, had never asked the Roman senators to ratify his own nomination as emperor. Diocletian put imperial succession in the hands of the gods, as was indicated by the elevated images of generic rulers standing atop column monuments who symbolically lifted the Tetrarchic augusti and caesares to the celestial realm, where they achieved permanence in an everlasting imperial order.

Perhaps as Tetrarchic emperors enacted the divinity of Hercules and Jupiter, the Tetrarchic column monuments emphasized the partial erasure of the rulers’ individual identities. It is likely that the four imperial statues surmounting the columns at the two Rostra were not portraits, but rather images of the emperor’s genius, or spirit.⁴⁸ There was, in fact, a golden statue of the Genius Populi Romani, the divinized spirit of the Roman people, on top of the Rostra that Aurelian (r. 270–275) had placed there.⁴⁹ Diocletian and Maximian were honored in an inscription—presumably situated directly on the Rostra platform and not linked to a column—that was for this statue of the Genius Populi Romani.⁵⁰ The Tetrarchic inscription accompanied the restoration of Aurelian’s genius of the Roman people and thereby presented Diocletian and Maximian as protectors of Rome’s citizens. Given the location of the Tetrarchic statues on top of the columns, the images were to be seen from far below, where the individual features of a likeness could not be perceived. In Tetrarchic group portraits from other cities each senior augustus looks like an elder version of the junior caesar, as can be witnessed in the Venetian porphyry statue group originally from Constantinople (figure 2.7). The generic and relatively undifferentiated group conveyed that the younger rulers acquired authority and power from their elders. The non-particularized porphyry images erased signs of individuality so as to transform the figures into roles linked to Hercules or Jupiter. It is likely that the images on top of the columns in Rome similarly avoided particularized physiognomy, thereby illustrating that the genii of the emperors depicted on top of the columns were a counterpoint to the genius of the Roman people displayed below on the platform.

Figure 2.7. Porphyry statue group of the Tetrarchs, façade of the Basilica of San Marco, Venice. (Photo Nino Barbieri)

The Tetrarchs shifted away from the military components of victory processions by delaying triumph celebrations after battle to coincide with the rituals celebrating five-, ten-, or twenty-year jubilees. The ceremonial arrival of Diocletian and Maximian into Rome was the only opportunity they had to personally use the two Rostra. Speeches played a significant role in a jubilee ritual and they were pronounced in front of the Tetrarchs’ five-column monuments; other themes such as those associated with triumph were implicated at the Rostra as well.⁵¹ The specific oration that addressed the Tetrarchs on that day in 303 does not survive. Panegyrics presented elsewhere praised the Tetrarchic emperors as the ones who refounded the empire. This idea was presented to Maximian with an oration composed in 291 for presentation in Trier on the birthday of Rome, April 21l. The panegyrist addresses Maximian directly: “You honor Rome’s birthday in that you celebrate the foundation of that city as if you yourself were its founder. In truth, O most sacred emperor, one might justifiably call you and your brother the founders of the Roman Empire, for you are what is almost the same thing, its restorers (restitutores) and although this is the birthday of this city, which marks the origin of the Roman people, it is the first days of your rule which mark the beginning of its salvation.”⁵² This text presented in Trier anticipates the Tetrarchic theme pertinent to the jubilee of 303 that the two emperors had restored Rome.

The senators of Rome expressed their disfavor with the first Tetrarchy. These aristocrats remained aloof and voiced bitter complaints to Diocletian and Maximian in 303, according to Lactantius, despite the architectural rebuilding projects through which the Tetrarchs had provided assistance to Rome.⁵³ The apparently vociferous complaints muttered by Romans during Diocletian’s visit of 303 caused Lactantius to report that following the celebrations the emperor was “unable to bear the freedom of speech practiced by the people of Rome.”⁵⁴ There is no documentation of the specific senatorial gripes, but the aristocrats must have been offended by the Tetrarchs’ failure to request the Senate’s ratification of the imperial appointments. The augmented power of Tetrarchic emperors effectively silenced the senatorial voices that could have toned down the authoritarian impulses of Diocletian and Maximian.⁵⁵ Finally, senators could have been offended by the rituals that, without senatorial approval, put the living rulers into the positions of gods.

Jubilee Ritual in Rome

Diocletian and Maximian arrived into the Roman Forum in 303 for the twentieth jubilee appearing as unapproachable rulers who were shielded from the public by their court officials. Audiences must also have been taken aback by the Tetrarchs’ regalia. Fourth-century documents reveal that Diocletian was innovative in wearing purple-dyed bejeweled silks while carrying the insignia of an emperor. Eutropius characterizes Diocletian’s garments as those of someone acquiring the trappings of divinized rule in that the Tetrarch “commanded that he be worshipped, where all previous emperors had been greeted . . . He ornamented his shoes and robes with precious jewels.”⁵⁶ This manner of self-presentation was at odds with a longstanding tradition that a ruler should behave in Rome as if equal in status to the senators.

The choice of a jubilee as the only occasion for Diocletian and Maximian to arrive in Rome signals that the Tetrarchs used the ritual in the traditional capital to renew the city’s past. Redeeming lapsed time had been ritualized by emperors during the centuries preceding Diocletian’s reign. Indeed, emperors traditionally took vows (vota) at the moment of accession so as to anticipate a decade of ruling continually, a period identified as the susceptum. The solutum, the fulfillment of the vow, was a moment that restituted the initial time of the vow. During the third century, most emperors had not occupied the office for ten years and consequently typically failed to reinstate the past.

The anniversary in 303 of joint rule for the Tetrarchs signaled the completion of the previously declared vows (vota soluta) to govern continually.⁵⁷ Presumably Diocletian and Maximian anticipated future jubilees to be celebrated in Rome. In the context of joint rulership among a college of four emperors, Diocletian and Maximian could ensure the longevity of rule and thereby they were more apt to fulfill the oaths, given that the collegial rulers all operated under the same vow. One emperor, performing the rites of renewal ten years after the initial vow, would be able to fulfill the vow to benefit the other augusti and caesares, who received consecration of the oath at the same time. In addition, Diocletian’s introduction of joint rule as a means of ensuring the longevity of his reign projected a desire for everlasting permanence in that newly appointed emperors could fulfill the solutum vows that had already been taken.

Diocletian and Maximian must have ritually progressed in Rome along the triumph route that led them into the city from the north. They proceeded through the Arcus Novus, a now-dismantled triumphal arch that commemorated Diocletian and Maximian.⁵⁸ One of the sculptural reliefs still exists and shows two female personifications supporting a shield upon which a third figure inscribes, “VOTIS X ET XX.”⁵⁹ This refers to the vows taken on the tenth jubilee in the hope that the oath would be fulfilled at the twentieth anniversary and resembles the presentation of the inscription within a shield on the Decennalia base. This seems to have accompanied a now-lost inscription, stating “VOTA X ET XX,” which corresponds to the suscepta vows taken as an oath in the hope of reaching the twentieth anniversary (to be earned after another decade of rule).⁶⁰ The epigraphic testimony from the Arcus Novus emphasizes that the vows taken by Tetrarchic emperors were ritually commemorated in processions for the purposes of synchronizing the imperial reigns.

The jubilee celebrations of 303 allowed Diocletian and Maximian to acquire honors from the victories achieved by the caesares. An important decision took place in Rome, where the two augusti decided to mark the apex of their careers by planning their joint retirement, which Eutropius tells us occurred “after a magisterial triumph over many nations.”⁶¹ Thus, the anniversary event featured vanquished troops representing those humiliated in various battles, including those subdued by the caesares. Constantius and Galerius shared in the honors of the procession despite their absence from Rome, as the augusti took the solutum for all four rulers. In 303 there was an emphasis on celebrating the major military success of Galerius over the Persians that took place in 298; yet additional victories were folded into the event as well. Panegyrics for earlier imperial rituals attest that the emperors had awaited an appropriate anniversary event for the triumph celebration.⁶² The procession of 303 paraded a range of conquered people whose vanquished appearance in front of the two augusti reinforced that these senior rulers shared credit for triumph with the absent junior emperors. Another fourth-century document records that the conquered Persians were obliged to march along in the procession and the text also mentions the subjugation of war prisoners from other nations. The same source documents the precious silver and gold that was distributed to the public after the emperors paraded through the streets with “thirteen elephants, six drivers, and two-hundred and fifty horsemen.”⁶³ The animals from distant lands symbolized the varied territories conquered by the Tetrarchs. The anniversary celebration of 303, then, presented the Tetrarchs as always dominating the whole world.

Diocletian and Maximian celebrated the jubilee together in Rome as if the ritual were a modified—and shared—victory procession. Eutropius mentions that the captured children, wives, and sisters of the defeated Persian general proceeded in front of the imperial chariot with the two emperors riding together in a single vehicle. On that very day, Eutropius further implies, the rulers decided to abdicate jointly.⁶⁴ After the cortège ascended the Capitoline Hill to reach the Temple of Jupiter Optimus Maximus, the emperors conferred about the joint abdication, apparently. A later source indicates that Maximian “lamented having taken an oath to him (Diocletian) in the Temple of Jupiter on the Capitoline.”⁶⁵ While the exact phrase of the oath that Diocletian and Maximian took on the Capitoline is not specified, this was the only meeting of the two where the emperors could have mapped out their plan for a joint retirement. Explicitly, the arrival in Rome was for the jubilee, according to Lactantius. Diocletian at the time felt his health was diminishing. Describing Diocletian, Lactantius asserts, “when good fortune had deserted him, Diocletian proceeded at once to Rome in order to celebrate there his vicennalia.”⁶⁶ The ambiguous evidence that Diocletian intended to discuss joint retirement plans with Maximian demonstrates that conflating a triumph procession with a jubilee underscored the synchronizing impulse that also was at play.

The two Rostra in the Roman Forum functioned as lasting installations that synchronized the celebrations of the first Tetrarchs and anticipated that additional jubilees would regularize the cycles of collegial rule. The eight imperial figures elevated upon columns from the two facing Rostra at either end of the Forum depicted the alternation from one Tetrarchic college to another in two groups of four. Column monuments and statues, then, offered a permanent representational scheme for rulers living outside of Rome, leaving a lasting memorial in the traditional capital.

The Tetrarchic Legacy

The retirement of Diocletian and Maximian had the unintended consequence of hastening the demise of the first Tetrarchy. In 306 Maxentius took control of Italy as a usurper. Subsequently, troops in Britain hailed Constantine as a caesar, but his appointment was not ratified by the legitimate emperors. Diocletian’s lack of success in ensuring the continuity of a non-dynastic college of emperors after 306 does not diminish the extraordinary influence of his reforms, particularly in orchestrating administrative changes and the division of the empire into eastern and western sectors. In Rome, Diocletian and Maximian introduced temporal renewal as the theoretical basis for restoring public buildings and updating urban space, which persisted long after the first Tetrarchy. To advertise the temporal cycles, Diocletian and Maximian used the Tetrarchic monuments on top of the Rostra at either end of the Forum’s central area as new interventions juxtaposed to preexisting features that effectively transformed the plaza from a site demonstrating aristocratic hierarchies to a precinct supporting the cyclical renewals of the past. The images on top of the columns in the Forum allowed Diocletian and Maximian to make amends for the absence of emperors from Rome by creating a permanent representation of their ideology of rule in place of their physical presence. Also, the Rostra monuments implied a new spatial paradigm in the open-air place for public assemblies, which the Tetrarchic ideology regularized by likening the four emperors to the cycles of the seasons. Adam T. Smith’s theory of politicized landscapes—a term capturing the architectural, geographic, spatial, and urban dimensions of complex societies—sees the imprints on cities and territories as profoundly ideological. Smith further analyzes landscapes by taking into account the evolving concepts of time that emerged with urban transformations, thereby analyzing how historical societies produce temporal concepts through spatial practices. In noting that restoration projects or similar interventions revised the past, Smith establishes that rulers occupied territories by taking possession of the history inscribed in that space. Of course, Rome offered preexisting strata that conditioned the way the city was experienced. Yet the Tetrarchic reconfiguration of the old Augustan Rostra together with Diocletian’s project that superseded the Rostra of Caesar’s Temple both provide clear instances in which repairs shaped political experiences.⁶⁷ In the end, the original Tetrarchic system could not fully coordinate succession and the non-hereditary rulership by an imperial college fell apart. Despite their failed ambitions, the Tetrarchs did produce urban planning successes that promoted the late antique ideology of collegial rule. In sum, the Tetrarchic emphasis on imperial ideology failed in its specifics, but promoted restored time as a key imperial message of the Forum’s central area.

Even two centuries after Diocletian’s rule, the idea that legitimacy was acquired through the preservation of Rome was generally accepted. During the sixth-century Gothic Wars, the Byzantine general Belisarius reportedly issued an impassioned plea for preserving Rome as a city whose built fabric could dictate its own destiny. At the time, Belisarius was about to recapture the city from the Ostrogoths under the king Totila. Aware that Rome could be controlled politically by protecting the built infrastructure, Belisarius aimed to deprive his adversaries of the privileges they might acquire by taking possession of Rome’s architectural heritage. In an account of the conflict, Procopius describes a persuasive letter crafted by Belisarius to discourage Totila from setting Rome on fire. Belisarius’ words staved off destruction by implying that a leader could achieve fame only by protecting the trajectory of history that was built up in Rome. Burning Rome, by contrast, would taint a ruler’s reputation forever. Procopius quotes from the letter.

Procopius implies that Totila hesitated to destroy Rome for the same reason that made the theft of building materials illegal: such acts would turn the perpetrators of harm into despised tyrants.⁶⁹ Totila never did burn Rome to the ground, even though the city indeed suffered from numerous sieges during the Gothic Wars. Generations following in the wake of Belisarius could chart their own paths to success, Procopius implies, by preserving the “memorials to the ability of them all” whose representations remained intact.

Procopius may only have had only the vaguest inklings about Diocletian’s projects in the Roman Forum. Nonetheless, public displays in Mediterranean cities illustrated that generations of rulers inherited the trajectory of the past by restoring buildings. In short, Procopius registers the lasting influence of the Tetrarchic idea of retrofitting the Forum, where memories of Rome’s earliest foundations could be renewed and dramatically reformulated through the zone’s transformation.

Conclusion

The ideology of Diocletian and Maximian became physically palpable by contextualizing exhibitions of statues and monuments in the restoration of buildings and in the installations of column monuments at the Rostra. Reworking Rome’s historical monuments into advertisements for joint rulership, the first Tetrarchy instigated a novel approach to the Forum that made collegial rule appear as if it were inherited from illustrious predecessors. Specifically, Diocletian and Maximian transformed the tradition of the solitary column monument into a serial display under the Tetrarchs that located emperors under the temporal stewardship of Jupiter and Hercules. Rites of renewal regulating the succession of each pair of augusti and caesares were to be celebrated at ten-year intervals, as the Tetrarchs implied by installing the Forum monuments. Diocletian and Maximian used these Rostra and anticipated that generations to come would do the same.