During or just after the reign of Rome's first emperor Augustus (r. 27 B.C.E.–14 C.E.), the Greek geographer Strabo penned his work Geographica and provided a valuable description of many of the peoples and places in the Greco-Roman world.1 When Strabo reported the “best accredited story of the founding of Rome,” he recounted the tale, “partly fabulous but partly closer to the truth,” of Rhea Silvia, a woman forced by her uncle Amulius to become a Vestal Virgin to assure she would remain childless, thereby preventing the birth of a potential political rival.2 Notwithstanding her sacred inviolability, Rhea Silvia was impregnated by the god Mars. She gave birth to Romulus and Remus, semidivine twin boys who grew into manhood, defeated Amulius and his sons, and established the foundations for the city of Rome.
Lacking natural defenses and usable arable land, the location for Rome's foundation was suitable “more as a matter of necessity than of choice.”3 For his part, Strabo forgave the early Romans for not beautifying their city, citing their understandable preoccupation with matters of government and war. The successors to Rome's mythical founders would eventually reduce its vulnerability by building protective circuit walls and defensive gates as early as the fourth century B.C.E. By the reign of Augustus, however, Strabo noted that circumstances had indeed changed. Rome's leaders of the late republic and the first imperial court had not neglected the city's infrastructure; rather they filled Rome with “many beautiful structures.”4
In fact, Pompey, the Deified Caesar, Augustus, his sons and friends, and wife and sister, have outdone all others in their zeal for buildings and in the expense incurred. The Campus Martius contains most of these, and thus, in addition to its natural beauty, it has received still further adornment as a result of foresight. Indeed, the size of the Campus is remarkable, because it affords space at the same time and without interference, not only for chariot-races and every other equestrian exercise but also for all that multitude of people who exercise themselves by ball-playing, hoop-trundling, and wrestling; and the works of art situated around the Campus Martius and the ground, which is covered with grass throughout the year, and the crowns of those hills that are above the river and extend as far as its bed, which present to the eye the appearance of a stage-painting – all this, I say, affords a spectacle that one can hardly draw away from. And near this campus is still another campus, with colonnades round about it in very great numbers, and sacred precincts, and three theatres, and an amphitheatre, and very costly temples, in close succession to one another, giving you the impression that they are trying, as it were, to declare the rest of the city a mere accessory. For this reason, in the belief that this place was holiest of all, the Romans have erected in it the tombs of their most illustrious men and women.5
This area known in Strabo's day as the “Campus Martius,” or “the Field of Mars,” was located not in the city proper but north of the Capitoline Hill, just outside of Rome's first defensive walls. Large and flat and, for much of the republican period, grassy and unencumbered by man-made structures, the Campus Martius was part of a floodplain framed by the Capitoline Hill to the south, the Tiber River to the west, the Pincian and Quirinal Hills to the east, and a narrow throat of land between the Tiber and the Pincian Hill to the north. Until the late imperial era, most of the region lay outside the pomerium, the mythical plow line or sacred furrow that delineated the city limits and relegated certain activities to one side (intrapomerial) or the other (extrapomerial). For example, according to long-standing republican tradition, rituals that sought divine approval for mortal actions could be performed within the pomerium, but Rome's own armed troops were forbidden to cross the pomerial boundary and enter the city unless expressly invited by the Senate.6 Soldiers mustering for war and citizens gathered for census counting, centuriate assemblies, and military unit assignments were relegated to the plain of the Campus Martius, outside the sacred line. Following a successful return from campaign, Roman legions would assume military formations on the open plain in preparation for the triumphal processions that snaked their way through the narrow city streets. In addition to troop assembly, certain foreign ambassadors were temporarily housed in the Campus Martius while they waited for an invitation to cross the pomerium.7 Moreover, the open field was also an ideal location for the construction of temples vowed by generals during the heat of battle with Rome's many enemies, some dedicated to foreign gods that could be worshiped only beyond the city walls. Likewise, cremation and burial rites were permitted only outside of the pomerial line; some of the most significant funerary structures were constructed in the Campus Martius, including the greatmausoleum of Rome's firstemperor.
The Field of Mars also was connected intrinsically to the foundation legends of the city. The Tiber that ran along its western boundary was the same flood-swollen river into which Rhea Silvia's twin sons were thrown, only to wash ashore in their cradle further downriver. Years later, according to one legend, Romulus, then Rome's sole king, ascended to heaven in a storm cloud from the center of the open field, where he had been mustering his troops for battle. Ultimately, this land “between the city and the Tiber” became, according to Livy, the property of Rome's last Etruscan king, Tarquinius Superbus.8 After the defeat and exile of Tarquinius in 509 B.C.E., the plain was once again reclaimed by Rome's Latin citizens and dedicated to the god Mars.9 Following the expulsion of the foreign despots, the area north of the pomerial line was known, according to Livy, simply as the Campus Martius, or “Field of Mars.”10
As it contained few structures until the third century B.C.E., the swampy plain north of the city accommodated large crowds on a periodic and usually seasonal basis. Soldiers mustered there in the spring and received discharge orders in the fall. Citizens gathered in the field for important religious festivals tied to the war god, such as the equestrian contest known as the October Horse and the holiday Anna Perenna on the Ides of March, in addition to remembrances every July to Romulus's death. As the location for triumphal parade formations, the Campus Martius received throngs of visitors on the dates set for the celebration of military victories. Lying in a floodplain and infested with mosquitoes in late summer, the plain was deemed ideal for periodic military training and festivals but not for daily urban activities. For five centuries after Rome's mythical founding, use of the field by Rome's residents was limited.
With the advent of the Punic Wars beginning in the mid-third century B.C.E., Rome expanded its military reach throughout the Mediterranean basin and north of the Alps. This resulted in the slow demise of the annual rhythm of warfare and, with it, the requirement of seasonal musters in the Field of Mars. No longer needed entirely for unobstructed troop exercises, the Campus Martius began to attract development that complemented its military and other public uses. The plundered treasures of foreign conquest pouring into the capital during overseas military adventures funded the construction. The scale and cultural importance of the Campus Martius made it an ideal location for the conspicuous and tangible display of political ambition. It was there that leading republican citizens constructed temples to provide lasting reminders of their personal successes and public munificence. Some temples were surrounded with beautiful colonnades, creating sacred precincts in an area that could accommodate vast enclosures. The marbled spaces served as repositories for extraordinary art and provided various “firsts” for the city, including the first temple entirely of marble and the first colonnade as a victory monument.
Notwithstanding the construction of temples and occasionally temporary wooden theaters, until the mid-first century B.C.E., the use of the Campus Martius by Rome's residents remained as it had been for centuries, a place for periodic gatherings and festivals. A significant transformation of the space began, however, when one of Rome's greatest generals, Gnaeus Pompeius Magnus (Pompey the Great), dared to erect a permanent venue for theatrical shows. He chose the flat, open plain as the ideal location for his enormous stone structure. Other buildings in the Campus Martius designed for entertainment as well as for bathing followed, and by the beginning of the common era, streams of visitors came to the field on a daily basis.
With the ascension to power of Augustus, the Field of Mars began its conversion into a showcase for imperial architecture and the physical manifestation of Rome's preeminence. At the time Strabo called the location of the Campus Martius the “holiest of all,”the open fields were quickly shrinking. Drained and leveled, the alluvial plain was filling from the south to the north with colonnades, theaters, an amphitheater, public baths, temples, and sacred precincts. Although the earlier martial functions of the plain were no longer critical to the success of Augustus's empire, inscriptions and carved images on triumphal arches, commemorative columns, and temple pediments proliferated throughout the Campus Martius to serve as reminders of the area's connection to the god of war and the foundation legends of Rome.
Over time, the Field of Mars was crammed with constructions of marble, concrete, and wood, until little of Mars's open field was left. Large private landholdings of famous generals such as Pompey and Marcus Agrippa were subdivided into beautiful public parks with pools and statuary and extraordinary edifices supported on carved columns and arches. Open spaces were now enclosed in colonnades, and the once flat topography developed a verticality created by buildings such as Pompey's theater and Augustus's mausoleum that reached as high as the Capitoline. Although its natural beauty was replaced by the man-made, the Campus Martius still remained highly susceptible to nature's powerful forces. Draining the marshes and raising the ground level did not prevent the terrible inundations from Tiber floods that periodically washed across the plain. Visitors to the field's numerous entertainment attractions in late summer were at risk of malaria outbreaks from the mosquitoes that frequented Rome's low-lying regions. Like many sectors of the ancient capital city, the northern plain suffered from fires that frequently razed buildings, thereby providing opportunities to build new structures with updated architectural designs and decorative programs. The interstices between temples, porticoes,baths, and theaters began to fill with commercial structures, houses, and apartment buildings. The pomerium shifted north, and in the third century C.E., the Aurelian Wall enclosed the Field of Mars within the city proper. The discernible features of the plain that distinguished it from the remainder of Rome were now blurred, as the Campus Martius was fully integrated into the urbs (city) that dominated the ancient world.
This book presents a case study of the repurposing of urban space in the Roman world and explores how uses that fit well with existing topographical features ultimately attracted architecture that forever transformed those features. It considers how the ideal topography and extrapomerial location of the Campus Martius allowed this sector to serve first as Rome's premier military assembly area and parade ground, space essential for a city-state that honored success in battle as the highest societal value.11 Through its connections to the activities of war, the Field of Mars offered the perfect location for important foundation myths of Rome, and this, in turn, influenced the types and decorative programs of buildings constructed within it. These structures as well as the availability of open, flat terrain in an increasingly crowded urban landscape, attracted more grandiose public works, which then reshaped the topography, altering forever the once open field of the war god Mars. Chapter 1 introduces the space and major monuments through a topographical overview, defining its limits and noting the changes from a swamp to a marble wonderland. Chapter 2 considers the relationship of the campus to Mars and the myths of Rome's foundation. The variety and location of temples built most often as vow fulfillments for the battlefield successes of ambitious republican generals are considered in Chapter 3. Previously a locale for occasional theatrical performances in temporary structures built near the steps of temples, the landscape of the Campus Martius evolved into a premier entertainment zone punctuated with permanent stone theaters, a horse racing track, and a stadium for Greek-style games. These structures are the focus of Chapter 4, whereas Chapter 5 considers the development of colonnades which created large sacred spaces around temples and parks next to theaters and which were filled with sculpture and painting from conquered nations. Water, both channeled and untamed, pervasively affected the Field of Mars, and its impact on the plain and its monuments is discussed in Chapter 6. Chapter 7 considers the imperial architectural programs that unified large sections of the Campus Martius and captured the martial and mythical past of the plain for the ideological and political agendas of Rome's emperors. The concluding chapter ties the various themes together and notes that, as Rome declined, the field that once awed Strabo now sheltered some of Rome's shrinking population among crumbling buildings. The extraordinary marbled edifices became monti of rubble that serve as the foundation materials for a modern city that, in turn, remains a palimpsest for its ancient glory. To assist the reader in his or her understanding of the space, Appendix A lists the major monuments of the Field of Mars in chronological order and within the context of major political events, while Appendix B may be consulted for the meaning of various architectural terms employed.