A major revolution occurred at the end of the 6th century (509 BC); the Romans expelled their king and replaced him and his family with a republican form of government. It wasn’t clean and easy. The Romans, now organized as an aristocratic oligarchy, had to not only fight their traditionally aggressive Etruscan, Latin and Italian neighbors but they also had to repel the revanchist royalists who were being supported by the Etruscan King of Clusium.

To complicate matters, a struggle between the ruling oligarchy (the Patricians) and the rest of the Roman citizenry (the Plebeians) pervaded every aspect of internal politics and foreign affairs, resulting in periodic crises that threatened the cohesion of the state. There were Plebeian secessions (walkout strikes) that resulted in political, legal and religious concessions by a reluctant Patrician order. One positive outcome of Plebeian agitation was the publishing of the Twelve Tables in the forum (451 BC). This made the law accessible to all citizens rather than leaving it to the interpretive monopoly of a self-serving Patrician pontificate.

Nevertheless, survival was a struggle. Archeological remains from the first two centuries of the republic indicate a significant drop in material wealth from the regal period. Grave sites were materially poorer, with little new public building taking place in the city.

A qualitative change, however, occurred around 390 BC. The state began to pay its citizens for fighting. This allowed the men to campaign year round rather than having to go home to plant and harvest their crops. They were, as a result, able to continuously besiege and eventually take the Etruscan city of Veii. Furthermore, the Camillan reforms changed the organization of the army and significantly altered its battlefield tactics. The infantry which had fought in a tight phalanx (shield wall) replaced this formidable but slow-moving formation with something much more flexible.

The defining event of the early republic again involved the Etruscan city of Clusium. This time the city begged the Romans for help against the invading Gauls. The Romans obliged the Clusians thereby bringing the wrath of the Gauls down upon themselves. An underprepared Roman army was defeated at Allia and Rome itself was occupied. Yet this traumatic event didn’t slow Roman expansionism, but to the contrary, accelerated it. So Rome emerged from the early republican period stronger and more determined than ever to expand its power and reach.