Gratus of Oloron was a 5th-century presbyter who served as the inaugural bishop of Oloron. Born in Lichos, he lived during a period of transition in the Visigothic kingdom, moving from the persecutions under King Euric to the relative tolerance provided by Alaric II. This shift allowed for the establishment of new Catholic bishoprics, including his own. He was a participant in the Council of Agde in 506, attending the assembly led by Caesarius of Arles.