Conquered by the Romans in 311 BC, Arretium became a military station on the via Cassia, the road to expansion by republican Rome into the basin of the Po. In the 3rd to 4th century, Arezzo became an episcopal place: it is one of the few cities whose succession of bishops are known by name without interruption to the present day, in part because they were the feudal lords of the city in the Middle Ages.