city of Veii; this defeat was later avenged at the Battle of Veii in 396 BC, wherein Rome destroyed the city. By the end of this period, Rome had effectively completed the conquest of their immediate Etruscan and Latin neighbours, and also secured their position against the immediate threat posed by the nearby Apennine hill tribes. Plebeians and patricians Beginning with their revolt against Tarquin, and continuing through the early years of the Republic, Rome's patrician aristocrats were the dominant force in politics and society. They initially formed a closed group of about 50 large families, called gentes, who monopolised Rome's magistracies, state priesthoods and senior military posts. The most prominent of these families were the Cornelii, followed by the Aemilii, Claudii, Fabii, and Valerii. The power, privilege and influence of leading families derived from their wealth, in particular from their landholdings, their position as patrons, and their numerous clients. The vast majority of Roman citizens were commoners of various social degrees. They formed the backbone of Rome's economy, as smallholding farmers, managers, artisans, traders, and tenants. In times of war, they could be summoned for military service. Most had little direct political influence over the Senate's decisions or the laws it passed, including the abolition of the monarchy and the creation of the consular system. During the early Republic, the plebs (or plebeians) emerged as a self-organised, culturally distinct group of commoners, with their own internal hierarchy, laws, customs, and interests. Plebeians had no access to high religious and civil office, and could be punished for offences against laws of which they had no knowledge. For the poorest, one of the few effective political tools was their withdrawal of labour and services, in a "secessio plebis"; they would leave the city en masse, and allow their social superiors to fend for themselves. The first such secession occurred in 494 BC, in protest at the abusive treatment of plebeian debtors by the wealthy during a famine. The patrician Senate was compelled to give them direct access to the written civil and religious laws and to the electoral and political process. To represent their interests, the plebs elected tribunes, who were personally sacrosanct, immune to arbitrary arrest by any magistrate, and had veto power over the passage of legislation. Celtic invasion of Italy By 390, several Gallic tribes were invading Italy from the north. The Romans were alerted to this when