Norman conquest of southern Italy

The Norman conquest of southern Italy lasted from 999 to 1194, involving many battles and independent conquerors. In 1130, the territories in southern Italy united as the Kingdom of Sicily, which included the island of Sicily, the southern third of the Italian Peninsula (including Benevento, which was briefly held twice), the archipelago of Malta, and parts of North Africa.

Itinerant Norman forces arrived in southern Italy as mercenaries in the service of Lombard and Byzantine factions, communicating swiftly back home news 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 50 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.

There is little evidence of Viking activity in Italy as a precursor to the arrival of the Normans in 999, but some raiding is recorded. Ermentarius of Noirmoutier, the Annales Bertiniani, and several additional Moorish sources provide accounts of Vikings based in Frankia (France), raiding in Iberia, then proceeding to raid in other parts of the Mediterranean around 860. In 860, according to an account by the Norman monk Dudo of Saint-Quentin, a Viking fleet co-commanded by Alstignus, believed to be Hastein, and Björn Ironside, landed in Italy seeking to sack the city of Rome. The Viking force arrived at the town of Luna, whose walls were too heavily defended for an outright assault. The force devised a plan to trick the town’s bishop into converting Hastein to Christianity. Once converted, Hastein faked his death with the final wish to be buried in the town's church. Entering with a small force with concealed weapons in the funeral procession, the force surprised the town guards and opened the city gates for the remaining Viking force. Upon learning that the town was not Rome, the Viking force raided the surrounding countryside before ultimately sailing back to Frankia.

Many Norsemen fought as mercenaries in Southern Italy, including the Varangian Guard led by Harald Hardrada, who later became king of Norway, who conquered Sicily between 1038 and 1040, with the help of Norman mercenaries, under William de Hauteville, who won his nickname Iron Arm by defeating the emir of Syracuse in single combat, and a Lombard contingent, led by Arduin. The Varangians were first used as mercenaries in Italy against the Arabs in 936. Runestones were raised in Sweden in memory of warriors who died in Langbarðaland (Land of the Lombards), the Old Norse name for southern Italy.

Later, several Anglo-Danish and Norwegian nobles participated in the Norman conquest of southern Italy, like Edgar the Ætheling, who left England in 1086, and Jarl Erling Skakke, who won his nickname ("Skakke", meaning bent head) after a battle against Arabs in Sicily. On the other hand, many Anglo-Danish rebels fleeing William the Conqueror joined the Byzantines in their struggle against Robert Guiscard, duke of Apulia, in Southern Italy.

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 some traditional sources of uncertain origin, 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".

The Salerno tradition was first recorded by Amatus of Montecassino in his Ystoire de li Normant between 1071 and 1086. Much of this information was borrowed from Amatus by Peter the Deacon for his continuation of the Chronicon Monasterii Casinensis of Leo of Ostia, written during the early 12th century. Beginning with the Annales Ecclesiastici of Baronius in the 17th century, the Salernitan story became the accepted history. Although its factual accuracy was questioned periodically during the following centuries, it has been accepted (with some modifications) by most scholars since.