Roger I of Sicily
Evelyn Jamison identifies Tancred's father with the margrave Odobonus who witnessed a document issued by Count Roger I of Sicily at Palermo in 1094 and with the Odobonus Marchisus who appears in a lawsuit of 1097, now archived at Agrigento. A third reference, to Othonus, who commanded a division of Count Roger's at Taormina in 1078, may also be to Tancred's father.