in the year 1000 southern Italy was divided into three distinct zones. Apulia and Calabria were ruled by the Byzantine empire, the island of Sicily by the Arabs (as it had been since the conquest of the ninth century) and the central mountains and the Campania were divided between three Lombard principalities, those of Capua (from a few miles north of Naples to the Monti Ausoni and the upper valley of the River Liri, the border with the papal states), Salerno in the south (from the Amalfitan peninsula down to the Gulf of Policastro) and Benevento (in the inland mountain district, from Avellino northwards to the Adriatic). In addition, to the north of the principality of Benevento, in the Abruzzi (roughly from the River Trigno northwards), lay a series of independent counties, partly Lombard, partly Frankish in origin, but this region was in almost every aspect, geographic, economic and social, separate from the south proper. On the west coast there were three small duchies, Gaeta, Naples and Amalfi, which had throughout the earlier middle ages retained a determined, if at times precarious, independence from their larger neighbours, the principalities of Capua and Salerno. Both Naples and Amalfi still acknowledged some dependence on the Byzantine empire, largely as a means of protection against the aggressive instincts of the Lombard princes.

Fragmented as the political divisions of southern Italy were, the cultural and religious divide was more complex still, for it did not coincide with the political boundaries. In the Byzantine dominions the population of northern and central Apulia was almost entirely Lombard, by this stage speaking a Latin-Romance dialect, and observing Latin religious rites. Southern Apulia and Lucania were more mixed, although the Greek part of the population was probably in the majority, and had been strengthened in Lucania by emigration from further south during the course of the tenth century. Calabria was mainly, and in the south entirely, Greek, but with still some Lombards in the area north of the Sila Grande which had in the ninth century been part of the principality of Salerno.