Guillaume "Bras-de-fer" (Iron Arm) Hauteville Count of Apulia
- Born: Abt 1005
- Died: 1046 about age 41
William of Hauteville (born before 1010 - died 1046), called Iron Arm (Guillaume Bras-de-fer in French and Guglielmo Braccio-di-ferro in Italian), was a Norman adventurer, son of Tancred of Hauteville, who, along with his younger brother Drogo, journeyed to the Mezzogiorno in the first half of the eleventh century (c.1035) in response to calls of aid from fellow Normans under Ranulph Drengot, count of Aversa.
Between 1038 and 1040, he fought in Sicily. It was there that he won his nickname Iron Arm, by single-handedly killing the emir of Syracuse during a sally at the siege of Syracuse while fighting for the Greeks. When the Greek general Giorgio Maniace (see Georgio as an unlinked individual in this software program, and his relationship to Harald Hardråda) publically humiliated the Salernitan leader, Arduin, the Lombards along with their mercenary Normans and the Varangian Guard contingent left. Maniace was consequently disgraced by the emperor in Constantinople and the new catepan of Italy, Michael Doukeianos, appointed Arduin ruler at Melfi. The Normans of William followed him and soon they were all in revolt with the Apulian Lombards. First Atenulf, Prince of Benevento, and then Argyrus, the nominal leaders of the revolt, were bought off by the Greeks and the Normans elected their own leader, ignoring Arduin. The revolt, originally Lombard, had become Norman in character and leadership.
In 1042, William petitioned Guaimar IV, duke of Salerno, for recognition of the Hauteville conquests. They received the lands around Melfi as a fief and proclaimed Guaimar Duke of Apulia and Calabria. The region (except for the capital, Melfi) was divided into twelve baronies for the benefit of the Norman leaders: Asclettin received Acerenza, Tristan received Montepeloso, Peter received Trani, and Drogo received Venosa. William himself, predominant among the norman leaders, received the lordship of Ascoli and was elected count. He married Guida, daughter of Guido, duke of Sorrento, and niece of Guaimar (Guido's brother). During his reign, he and Guaimar began the conquest of Calabria and he built the great castle at Squillace.
His titles were never confirmed by the Holy Roman Emperor. His successor, his brother Drogo, would be legally called Count of the Normans in all Apulia and Calabria (Comes Normannorum totius Apuliae e Calabriae), and so William is usually titled likewise.