George Maniakes (Greek: Γεώργιος Μανιάκης, transliterated as Georgios Maniaces, Maniakis, or Maniaches, Italian: Giorgio Maniace) (died 1043) was a prominent Byzantine Greek general during the 11th century, he was the catepan of Italy in 1042. He is known as Gyrgir in Scandinavian sagas. He is popularly said to have been extremely tall and well built, almost a giant.
Maniakes first became prominent during a campaign in 1030–1031, when the Byzantine Empire was defeated at Aleppo but went on to capture Edessa from the Arabs. His greatest achievement was the partial reconquest of Sicily from the Arabs beginning in 1038. Here, he was assisted by the Varangian Guard, which was at that time led by Harald Hardrada, who later became king of Norway. There were also Norman mercenaries with him, under William de Hauteville, who won his nickname Iron Arm by defeating the emir of Syracuse in single combat. However, he soon ostracised his admiral, Stephen, whose wife was the sister of John the Eunuch, the highest ranking man at court, and, by publicly humiliating the leader of the Lombard contingent, Arduin, he caused them to desert him, with the Normans and Norsemen. In response, he was recalled by the emperor Michael IV, also brother-in-law of Stephen. Although the Arabs soon took the island back, Maniakes' successes there later inspired the Normans to invade Sicily themselves.