<P> In 751 the Lombards seized Ravenna and the Exarchate of Ravenna was abolished . This ended the Byzantine presence in central Italy (although some coastal cities and some areas in south Italy remained under Byzantine control until the 11th century). Facing a new Lombard offensive, the papacy appealed to the Franks for aid . In 756 Frankish forces defeated the Lombards and gave the Papacy legal authority over all of central Italy, thus creating the Papal States . However, the remainder of Italy stayed under Lombard (such as Benevento and Spoleto) or Byzantine (such as Calabria, Apulia and Sicily) control . </P> <P> In 774, upon a Papal invitation, the Franks invaded the Kingdom of Italy and finally annexed the Lombards; as a reward the Frankish king Charlemagne received papal support . Later, on December 25, 800, Charlemagne was also crowned emperor of the Holy Roman Empire by the pope, triggering controversy and disputes over the Roman name . A war between the two empires soon followed; in 812 the Byzantines agreed to recognize the existence of two Roman Empires in return for an assurance that the remaining Byzantine possessions in Italy would be uncontested . </P> <P> Throughout this period, some coastal regions, and all of southern Italy, remained under Byzantine or Lombard control . The Imperial authority never extended much south of the Italian Peninsula . Southern Italy was divided amongst the two Lombards duchies of Spoleto and Benevento, who accepted Charlemagne's suzerainty only formally (812), and the Byzantine Empire . Coastal cities like Gaeta, Amalfi, Naples on the Tyrrhenian Sea, and Venice on the Adriatic Sea, were Latin - Greek enclaves who were becoming increasingly independent from Byzantium . A conquest of Benevento, otherwise, would have meant the total encompassment of the Papal territories, and probably Charlemagne thought it was good for his relationships with the Pope to avoid such a move . The age of Charlemagne was one of stability for Italy, though it was generally dominated by non-Italian interests . The separation with the Eastern world continued to increase . Leo III was the first Pope to date his Bulls from the year of Charlemagne's reign (795) instead of those of Byzantine emperors . This process of isolation from the Eastern Empire and connection with the Western world of France and Germany, which had started three centuries before, was completed at the beginning of the 9th centuries . Sicily, Calabria, Puglia and the marine cities were the main exceptions to this rule . </P> <P> After the death of Charlemagne (814) the new empire soon disintegrated under his weak successors . The equilibrium created through the great emperor's charisma fell apart . This crisis was due also to the emergence of external forces, including the Saracen attacks and the rising power of the marine republics . Charlemagne had announced his division of the Empire in 806: the Lombard - Frank reign, together with Bavaria and Alamannia, was to be handed over to his son Pepin of Italy . </P>

Why did the german rulers keep trying to take over italy during the later middle ages