The Norman conquest of southern Italy spans most of the 11th and 12th centuries, involving many battles and many independent players conquering territories of their own.

Only later are these territories in southern Italy united as the Kingdom of Sicily, which includes not only the island of Sicily, but also the entire southern third of the Italian Peninsula (save Benevento, which they do briefly hold on two occasions) as well as the archipelago of Malta and parts of North Africa.Immigrant Norman brigands acclimatize themselves to the Mezzogiorno as mercenaries in the service of various Lombard and Byzantine factions, communicating news swiftly back home about the opportunities that lie in the Mediterranean.

These aggressive groups aggregate in various places, eventually establishing fiefdoms and states of their own; they succeed in unifying themselves and raising their status to one of de facto independence within fifty years of their arrival.Unlike the Norman conquest of England (1066), which takes place over the course of a few years after one decisive battle, the conquest of southern Italy is the product of decades and many battles, few decisive.

Many territories are conquered independently, and only later are all unified into one state.

Compared to the conquest of England, it is unplanned and unorganized, but just as complete.