Hosius of Corduba (c. 256–359), also known as Osius or Ossius, was a bishop of Corduba (now Córdoba, Spain) and an important and prominent advocate for Homoousion Christianity in the Arian controversy that divided the early Christianity. He probably presided at the First Council of Nicaea and also presided at the Council of Serdica. After Lactantius, he was the closest Christian advisor to Emperor Constantine the Great and guided the content of public utterances, such as Constantine's Oration to the Saints, addressed to the assembled bishops. Life He was born in Corduba in Hispania, a province of the Roman Empire. Elected to the see of Corduba about 295, he narrowly escaped martyrdom in the persecution of Maximian. In 300 or 301 he attended the provincial Synod of Elvira (his name appearing second in the list of those present), and upheld its severe canons concerning such points of discipline as questions concerning clerical marriage, and the treatment of those who had abjured their faith during the recent persecutions. The Council appears to have had Novatianist tendencies and held a strict view that refused readmission to those baptized Christians who had denied their faith or performed the formalities of a ritual sacrifice to the pagan gods under pressures of persecution. In 313 he appears at the court of Constantine the Great, mentioned by name in a constitution directed by the emperor to Caecilianus of Carthage in that year. He is not listed among the attendees of the Synod of Arles of 314, but may have been in attendance upon the emperor, who was engaged in his first war with Licinius in Pannonia. As early as 320 or 321 Alexander, Bishop of Alexandria, convoked a council at Alexandria at which more than one hundred bishops from Egypt and Libya anathematized Arius, his deacon. In autumn 324 Hosius was the bearer of Constantine's letter to Bishop Alexander and Arius, in which he urged them to reconcile. After the Synod in Alexandria, Hosius led another synod in Antioch probably on the occasion of the election of Eustathius, after the death of Philogonius on November 324. In this synod, bishops supporting Arius were suspended and a general synod was announced which would be held in Ancyra. Emperor Constantine eventually moved the convocation to the First Council of Nicaea which opened on 20 May 325. Hosius probably presided over it, as his name appears first on the