The war with Veii played an important role in the expansion of the Roman Empire. The war, which ended in 410 BC, set in motion a completely different Roman army. The army was no longer a voluntary militia, but a paid and contractual organization. The "Roman victory ended Rome's most threatening neighbor and began to rise to prominence in the central Italian peninsula" (www.warandgameinfo.com). Another important factor that contributed to the expansion of the Roman Empire was the sack of Rome by the Romans. Gauls in 390 BC. “The Romans were completely stunned by the wild and undisciplined charge of the howling Gauls. The Romans' tight phalanx, a military formation they had adopted from the Greeks of southern Italy, collapsed and the Romans fled” (Kidner, 129). The dismissal left the Romans determined to prevent and avoid similar consequences in the future. After the Gauls' sacking of Rome concluded, Rome became obsessed with the security of its empire and acutely aware of all potential threats. “After the sack of the Gauls, the Romans were frightened by their powerful neighbors and sometimes launched preemptive attacks against peoples they believed were becoming too powerful” (Kidner, 129). Rome became a walled city that would not let any foreign soldiers pass through its gates from the end of the sack in 390 BC until 410 AD, earning it the nickname the Eternal City. The Roman mantra of Lex Fetiale, which forbade Rome from going to war unless besieged or asking for aid, was suddenly much easier to justify than before. The Romans would use the Lex Fetiale to expand their empire through the method of incorporation. As Rome expanded, due to a perceived threat or re...... middle of paper ...... established the principate, where it established several legates to help govern the expanding empire. The system allowed the Emperor to maintain control, but also to step aside and allow others to take the lead if necessary. If Augustus had not implemented this new form of government, Rome would have been torn apart several years before the fall of the Empire. His form of government proved strong enough to support people like Caligula and Tiberius, who were more concerned with his special interest museum than with being emperor. Works Cited Andrews, Stephen J. “Western Civ 1.” History 1101-105. Central New Mexico Community College, Albuquerque. 2011. Conference. Kidner, Frank L. Making Europe: People, Politics and Culture. Boston, MA: Houghton Mifflin, 2009. “SIEGE OF VEII” print. War and gaming. Internet. May 1 2011. .