The history of Rome is formed by the endless cycle of conquest and assimilation. From the very beginning, Rome grew by conquering neighbors and assimilating them into Roman culture. The Romans defeated the Latin League and engulfed the league into their dominion. The same thing happened with the Celts, Samnites, and other foes Rome faced in the way of expansion. Accordingly, expansionism and militarism were deeply rooted in the basis of Roman culture and shaped Rome as it became a territorial behemoth.
Expansion was the Roman ethos. Prowess in military campaigns was glorified within Roman society, and warriors gained respect from the populace. Expansionism shaped Roman culture by driving statewide support from the populace to raise military campaigns for glory and honor. Displaying one’s valor was the best way to get promoted and earn a higher place in society. Famed Julius Caesar also earned the title of centurion by showing off military prowess in the battle. The epitome of Roman culture that signifies the importance of the military in society is the Senate. Initially, to become a Roman senator, one was required to have served in the army. Even after, serving in the Roman army was necessary if one sought to gain political success and popularity. Similarly, the most important event in ancient Rome was the Triumphus–a military parade to celebrate the victory of war, and it was considered the greatest honor one could achieve in Rome.
Another factor that military expansion played in Rome was economic development. The Romans promoted expansionistic ideals and military campaigns not only for personal glory but also for the societal benefits that followed. The development of the Roman agricultural estate system, aka Latifundium, raised tremendous demand for a labor force, most of which consisted of war slaves. More slaves to work on the plantation meant more free Roman men to serve in the military. Besides slaves, Romans also brought loot from battles and exploited resources from conquered territories, enriching the Italian peninsula as one of the wealthiest and most prominent regions of the Mediterranean.
Rome modeled Sparta in its expansionistic policies and popular worship of militarism. However, Rome differed from Sparta and many other military states in history in that Rome operated in a stable system. Rome did not expand as quickly as the empires of Greece, Persia, or Assyria. Rome followed a repeating cycle of conquest, assimilation, and adoption of captives as slaves to serve on plantations, which provided a solid foundation to initiate the next campaign.