Bp. of Córdoba from c.295. He seems to have been Constantine's ecclesiastical adviser from 313 to 325. In the early stages of the Arian struggle he was sent to Alexandria to investigate and it was apparently as a result of his report that the Emperor summoned the Council of Nicaea (325). He played an important part in this Council and presided over the anti-Arian Council of Sardica in 343. His support of St Athanasius led to his banishment in 355. At the Synod of Sirmium (357) he signed the ‘Blasphemy’ and was allowed to return to his diocese.