Hilary of Poitiers received a Neoplatonic education in his hometown, which later influenced his Christian thought (Origen was one of his favorite authors). His search for the meaning of human life and his reading of the Bible led him to convert to Christianity. When he was baptized, he was already married and the father of a daughter, Abra, whom he loved dearly. He was chosen as bishop of Poitiers at the height of the Arian crisis. In 356, the Arian synod of Béziers had him exiled to Phrygia.
In the East, Hilary had the chance to deepen his understanding of the Trinitarian question. There he wrote the last nine books of his great work De Trinitate, which consists of twelve in total. Even in exile, he remained active: the faithful of Poitiers continued loyal to him, and he guided his diocese through his vicars. He entered the theological debate with new strength, enriched by the thought of the Eastern Fathers. He worked to restore unity between the homoousians of the East and the Western Church, and he defended himself in writing against attacks. His intervention at Seleucia annoyed the Arians so much that they asked Emperor Constantius to send Hilary back to Gaul. After four years of exile, he returned to Poitiers. There he welcomed as a disciple Saint Martin, the future bishop of Tours.
Back in Gaul, Hilary worked tirelessly to restore orthodoxy. Naturally conciliatory—yet courageous when needed, even writing against the emperor—he obtained good results, though not always. He was forced to depose Saturninus, bishop of Arles, but failed in Milan in his struggle against the Arian bishop Auxentius, who was clever and politically skilled.
In his later years, Hilary devoted himself more to study than to controversy. He wrote a highly praised commentary on the Psalms, personally copied a Gospel book, composed hymns, and published exegetical works.
He died in 367. Though not a theologian or writer by vocation (but rather by necessity), Hilary became one of the great clarifiers of the Christian faith. With the help of reason, he advanced the understanding of revelation and gave it systematic form. He represents in a special way the union of Western and Eastern theological thought. Pope Pius IX later declared him a Doctor of the Church.
His ancient feast day was January 13. Because of the octave of Epiphany, from the 13th century the celebration was moved to January 14, but the current calendar has restored the original date, already attested by the Martyrologium Hieronymianum in the 6th century.
