of the Empire, now centred on Constantinople, invaded Italy in the early 6th century, and the generals of emperor Justinian, Belisarius and Narses, conquered the Ostrogothic kingdom after years of warfare, ending in 552. This conflict, known as the Gothic Wars, destroyed much of the town life that had survived the barbarian invasions. Town life did not disappear, but they became smaller and considerably more primitive than they had been in classical Roman times. Subsistence agriculture employed the bulk of the Italian population. Wars, famines, and disease epidemics had a dramatic effect on the demographics of Italy. The agricultural estates of the Roman era did not disappear. They produced an agricultural surplus that was sold in towns; however slavery was replaced by other labour systems such as serfdom. The withdrawal of Byzantine armies allowed another Germanic people, the Lombards, to invade Italy. Cividale del Friuli was the first main centre to fall, while the Byzantine resistance concentrated in the coast areas. The Lombards soon overran most of the peninsula, establishing a Kingdom with capital in Pavia, divided into a series of dukedoms. The areas in central-northern Italy which remained under Byzantine control (mostly the current Lazio and Romagna, plus a short corridor between Umbria that connected them, as well as Liguria) became the Exarchate of Ravenna. Southern Italy, with the exception of Apulia, current Calabria and Sicily, were also occupied by the two semi-independent Lombard duchies of Spoleto and Benevento. Under the imperial authority remained also much of the ports, which eventually turned into actually independent city-states (Genoa, Pisa, Venice, Amalfi). Rise of the Patriarchate of Rome The Church (and especially the bishop of Rome, by now styled the pope), had played an important political role since the time of Constantine. In the politically unstable situation after the fall of the western empire, the Church often became the only stable institution and the only source of learning in western Europe. Even the barbarians had to rely on clerics in order to administer their conquests. Furthermore, the Catholic monastic orders, such as the Benedictines had a major role both in the economic life of the time, and in the preservation of classical culture (although in the east the Greek authors were much better preserved). After the Lombard invasion, the popes were nominally subject to the eastern emperor, but often received little help from Constantinople, and had to fill the lack of