For 10 points, name this Norman knight who drove the Byzantine Empire out of Italy.
An anecdote claims that this man ambushed his father-in-law William Mascabeles, and pulled out his teeth one-by-one to disgorge him of his money. This man's wife Sikelgaita helped rouse his troops at a battle in which many of his enemies died in a blaze that burned down a church named for the archangel Michael. Pope Nicholas II signed the Treaty of Amelfi with this commander, who collaborated with Richard of Capua to defeat the Swabians at the Battle of Civitate. This man, who spent three years besieging the city of Bari, died on the island of Kefalonia after he rescued (*) Gregory VII from the Castel Sant' Angelo during Henry IV's siege of Rome. The duchy of Apulia and Calabria was created for this son of the knight Tancred, who worked with his son Bohemond of Taranto to defeat Alexios Komnenos at the Battle of Dyrrahachium. For 10 points, name this Norman knight who drove the Byzantine Empire out of Italy.
An anecdote claims that this man ambushed his father-in-law William Mascabeles, and pulled out his teeth one-by-one to disgorge him of his money.
Robert Guiscard [or Robert de Hauteville; prompt on Robert or Guiscard] 