The identity of Geoffrey's parents is unknown, but it is believed that his mother was a daughter of
Tancred of Hauteville and it has been speculated that his father was Armand of Mortain. According to
Goffredo Malaterra, Geoffrey conquered most of his lands with his own energy (
sua strenuitate) and without the help of Robert Guiscard. Thus, when, in 1067, Guiscard demanded homage for the castle of
Montepeloso, Geoffrey refused. Robert brought him to heel in the subsequent war and Geoffrey did homage. Among the other lands Geoffrey had conquered from the
Byzantines were
Polignano and
Monopoli. Geoffrey joined his cousins
Abelard and
Herman, his brother
Robert, and
Henry, Count of Monte Sant'Angelo in the rebellion of 1079–1082, while the Guiscard was away fighting the
Byzantine Empire in the
Balkans. His brother died in July 1080 and Abelard a year later. While he was besieging
Oria, a city on the
Via Appia between Brindisi and
Taranto, Robert returned at
Otranto and began to march towards him. Geoffrey, though he had numerous troops, fled anyway. By 1083, Geoffrey was reconciled to Robert Guiscard and accompanied him on his final Byzantine expedition. After Guiscard's death in 1085, Geoffrey became the vassal of Guiscard's son
Roger Borsa, although a troublesome one. In 1088 Roger had to cede this
vassalage to his older, disinherited brother
Bohemond of Taranto after he had waged a successful campaign against Roger, thus gaining also access to Brindisi. Geoffrey was present at the synod held in
Melfi in 1089 but did not participate in
Bohemond's contingent during the
First Crusade. Geoffrey hosted in the winter of 1099/1100 the returning crusader
Robert Curthose, duke of Normandy, who had gained considerable reputation due to the success of the First Crusade which most likely also played a role in convincing Geoffrey to marry his daughter Sybil to Robert. It is likely that Robert had met Sybil in the winter of 1096/97 while on the way to the
Holy Land and, according to
Orderic Vitalis, had fallen in love with her. Geoffrey died, most likely in Brindisi, in February 1104 or April 1107. He was a patron of the local
monasteries and seems to have been fairly wealthy as his dowry enabled at least partially Robert Curthose to redeem his duchy which he had loaned to his brother
William Rufus in order to finance his expedition. ==Marriage and issue==