Norman conquest of Sicily

The Norman conquest of southern Italy spanned most of the 11th and 12th centuries, involving many battles and independent conquerors. Only later were these territories in southern Italy united as the Kingdom of Sicily, which included the island of Sicily, the southern third of the Italian Peninsula (except Benevento, which was briefly held twice), the archipelago of Malta and parts of North Africa.

Itinerant Norman knights arrived in the Mezzogiorno as mercenaries in the service of Lombard and Byzantine factions, communicating news swiftly back home about opportunities in the Mediterranean. These groups gathered in several places, establishing fiefdoms and states of their own, uniting and elevating their status to de facto independence within fifty years of their arrival.

Unlike the Norman conquest of England (1066), which took a few years after one decisive battle, the conquest of southern Italy was the product of decades and a number of battles, few decisive. Many territories were conquered independently, and only later were unified into a single state. Compared to the conquest of England it was unplanned and disorganised, but equally complete.

The earliest reported date of the arrival of Norman knights in southern Italy is 999, although it may be assumed that they had visited before then. In that year, according to several sources, Norman pilgrims returning from the Holy Sepulchre in Jerusalem via Apulia stayed with Prince Guaimar III in Salerno. The city and its environs were attacked by Saracens from Africa demanding payment of an overdue annual tribute. While Guaimar began to collect the tribute the Normans ridiculed him and his Lombard subjects for cowardice, and they assaulted their besiegers. The Saracens fled, booty was confiscated and a grateful Guaimar asked the Normans to stay. They refused, but promised to bring his rich gifts to their compatriots in Normandy and tell them about possibly lucrative military service in Salerno. Some sources have Guaimar sending emissaries to Normandy to bring back knights, and this account of the arrival of the Normans is sometimes known as the "Salerno (or Salernitan) tradition".

...
Wikipedia