Olegarius was a 12th-century prelate who served as the Bishop of Barcelona starting in 1116 and later became the Archbishop of Tarragona in 1118. Born into a noble Barcelona family around 1060, he held various positions including provost and abbot of the monastery of Saint-Ruf. A close advisor to Count Ramon Berenguer III, he frequently accompanied the ruler on military expeditions. He was a significant figure in ecclesiastical reforms and played a central role in the restoration and resettlement of the Tarragona region following its reconquest.