In the years following the establishment of the republic, the Romans fought numerous wars with their neighbors on the Italian peninsula. The Roman army was made up primarily of citizens of Rome organized into legions for military campaigns. War also involved diplomacy, and at an early date, Romans learned the value of alliances, which became a distinguishing feature of Roman expansion in Italy. Alliances with the towns around them in Latium provided a large population that could be tapped for military needs. Some of these townspeople were organized into troops called auxiliaries who fought with the legions.

In 387 B.C.E., the Romans suffered a major setback when the Celts—or Gauls, as the Romans called them—invaded the Italian peninsula from the north, destroyed a Roman army, and sacked the city of Rome. (For more on the Gauls, see "Celtic and Germanic People in Gaul and Britain" in Chapter 7.) More intent on loot than on conquest, the Gauls agreed to abandon Rome in return for a thousand pounds of gold. As the story was later told, when the Gauls provided their own scale, the Romans howled in indignation. The Gallic chieftain Brennus then threw his sword on the scale, exclaiming “Vae victis” (woe to the conquered). These words, though legendary, were used by later Romans as an explanation for why they would not surrender, and the city of Rome was not sacked again until 410 C.E.

The Romans rebuilt their city and recouped their losses. They brought Latium and their Latin allies fully under their control and conquered Etruria (see Map 5.1). Starting in 343 B.C.E., they turned south and grappled with the Samnites in a series of bitter wars for the possession of Campania. The Samnites were a formidable enemy and inflicted serious losses on the Romans; in response the Romans reorganized their army to create the mobile legion, a flexible unit of soldiers capable of fighting anywhere. The Romans won in the end and continued their expansion southward. Alarmed by Roman expansion, the Greek city of Tarentum in southern Italy called for help from Pyrrhus (PIHR-uhs), king of Epirus in western Greece, in 280 B.C.E. Pyrrhus won two furious battles but suffered heavy casualties—thus the phrase “Pyrrhic victory” is still used today to describe a victory involving severe losses.

The Romans and the Carthaginians had made a series of treaties to help one another (see page 127), and the Carthaginians attacked Sicily, drawing the armies of Pyrrhus away from Italy for a while and relieving pressure on the Romans. The Romans threw new legions against Pyrrhus’s army, which in the end left southern Italy. The Romans made formal alliances with many of the Greek cities in the south then turned north again. Their superior military institutions, organization, and large supply of soldiers allowed the Romans to conquer or take into their sphere of influence most of Italy by about 265 B.C.E.

As they expanded their territory, the Romans spread their religious traditions throughout Italy, blending them with local beliefs and practices. Religion for the Romans was largely a matter of honoring the state and the family. The main goal of religion was to secure the peace of the gods, what was termed pax deorum, and to harness divine power for public and private enterprises. Religious rituals were an important way of expressing common values, which for Romans meant those evident in their foundation myths: bravery, morality, seriousness, family, and home. Along with the great gods, the Romans believed in spirits who inhabited fields, forests, crossroads, and even the home itself. These spirits were to be honored with rituals and gifts so that they would be appeased instead of becoming hostile.

Victorious generals made sure to honor the gods of people they had conquered and by doing so transformed them into gods they could also call on for assistance in their future campaigns. Greek deities and mythical heroes were absorbed into the Roman pantheon. (See “Picturing the Past: The Temple of Hercules Victor.”)

Once they had conquered an area, the Romans built roads. These roads provided an easy route for communication between the capital and outlying areas, allowed for the quick movement of armies, and offered an efficient means of trade.

In politics the Romans shared full Roman citizenship with many of their oldest allies, particularly the inhabitants of the cities of Latium. In other instances they granted citizenship without the franchise, that is, without the right to vote or hold Roman office. These allies were subject to Roman taxes and calls for military service but ran their own local affairs. The extension of Roman citizenship strengthened the state and increased its population and wealth, although limitations on this extension would eventually become a source of conflict (see page 138).