The Italic tribes were an Indo-European people who migrated across the Alps from east-Central Europe in 1800 BC. The Italic tribes divided into several peoples, spreading from the Po Valley in the north and travelling to central and southern Italy. In the 1200s BC, Celts from Switzerland, eastern France, and southwestern Germany entered Lombardy and eastern Piedmont in northern Italy, mixing with the local Ligurians. In the region south of the Tiber, the Latins emerged, while the Veneti appeared in the northeast of the peninsula. By the mid-1st millennium BC, the Latins of Rome were growing in power and dominance, and several non-Italic Etruscans formed the Latin League against the Romans. After the Latins liberated themselves from Etruscan rule in 509 BC, they formed the Roman Republic, and they also became enemies with the Samnites. The Romans began to conquer the peninsula, and, following the Social War of the 1st century BC, all Italic tribes (except the Celts of the Po Valley) were granted Roman citizenship. The Italic peoples were quickly Romanized and came to speak Latin.