As already stated, the later ancient tradition maintained that Servius Tullius laid the foundations for the republic by his creation of the comitia centuriata, a popular assembly based upon the census and the military obligations of the citizens to the state. This assembly took its name from centuria, a military unit of the legion. In later historical times each legion was composed of 60 centuries, and in theory each century contained 100 men. The obvious military character of this assembly is indicated by its powers and place of meeting. Under the republic this body was responsible for electing all officials who exercised any form of imperium, which involved the raising and commanding of troops or the exercise of jurisdiction: consuls, praetors, censors, and curule aediles. These were the curule magistrates. Besides having the power to legislate by voting in favor of proposals placed before it by a curule magistrate, this assembly voted on declarations of war and ratified treaties and even acted as a high court in capital cases. Since it was considered to be an army sitting as an assembly, it was not permitted to convene within the sacred boundary (pomerium) of the city but always met in the Campus Martius, the Field of Mars, a large plain located on the northern fringe of the city and enveloped by the bend of the Tiber River.
The origin of the Servian organization does in fact seem to fit the historical context of Rome in the sixth century.4 Our current state of knowledge, based upon rather limited archaeological evidence and a critical examination of Roman traditions, suggests that Rome began to emerge as a self-conscious embryonic state during the last quarter of the seventh century. At this time the level of the Roman Forum, which had hitherto been prone to flooding from the Tiber, was raised and paved over with gravel for the first time to serve as the political and religious center of the community. In this area, for example, were now erected the Senate House, the Temple of Vesta, and the Regia. Over the course of the sixth century more temples were built, testifying to organized public religion and a sizable economic surplus. It is also likely that the size of Rome’s population and territory continued to expand, and the Roman community began to shape itself into a well organized city-state, so that by the beginning of the republic in 509 Rome was the largest of the Latin communities in Latium and probably rivaled the largest city-states north of the Tiber River in Etruria.
Part of this complex process of state formation during the sixth century is likely to have been the introduction of Greek hoplite warfare into Roman society.5 The hoplite panoply consisted of a helmet, a corselet, greaves, shield, and thrusting spear. The first four items were worn to protect the warrior. The shield was circular, measured about three feet in diameter, and was held on the left forearm by an armband and handle. The spear was about six feet long, was grasped overhand with the right hand in the middle of the shaft, was held near shoulder height, and was used to stab at one’s adversary. Hoplite warriors stood together in a tight formation, side by side and one behind the other in files usually eight to twelve men deep. They stood next to one another, so that their shields touched and presented a solid front to the enemy. Hoplite warfare originated in mainland Greece around 650, spread quickly throughout all Greek city-states (including the colonies in Sicily and southern Italy), and became the established method by which the Greeks fought their wars for the next three centuries until it succumbed to and was replaced by the Macedonian phalanx of pikemen.
The introduction of hoplite organization into Greek city-states during the seventh and sixth centuries is generally regarded as one of several important indications of state formation; and there is no reason why the same should not be assumed to have applied to the contemporary communities of central Tyrrhenian Italy, including Rome. The uniformity of the typical hoplite phalanx and the regularity with which it was imposed upon a state’s adult male population clearly reflect the rise of the state with rational institutions and with the ability and need to organize its citizenry into a systematic scheme for warfare. Hoplite citizens had to provide themselves with their own armor and weapons. Thus, the existence of a hoplite class within a community was predicated upon relative economic prosperity and a society possessing a sizable number of independent peasant farmers and artisans. In addition, it was the general rule among these city-states that the obligation of arming oneself to fight on behalf of one’s community entitled the hoplite warrior to the political right of belonging to and of voting in the citizen assembly.
Hoplite panoplies have been discovered in the so-called Tomb of the Warrior at Vulci on the Etruscan coast dating to c. 530, as well as in a tomb at Lanuvium in Latium dating to the early fifth century.6 Thus, the later ancient tradition that ascribed a major military reform to Rome’s sixth king in the middle of the sixth century can be associated with the introduction of the hoplite organization into the Roman state. The military system of the 30 curiae and three archaic tribes can probably be best dated to the period of Rome’s early unification during the seventh century; whereas the centuriate organization that supplanted it came into being toward the close of the regal period. By that time the site of Rome had experienced considerable urban growth and development. Besides a rural countryside inhabited by an emerging landed elite and a peasant population, the city itself possessed a growing class of artisans and craftsmen of all sorts. Increased economic activity and opportunities must have attracted immigrants; and it is generally supposed that the centuriate organization was devised at this time to replace the now outmoded curiate system and to harness the military potential of Rome’s growing population. The result was a hoplite phalanx recruited from new territorial districts called tribes.