Married, one daughter, baptized as an adult. B. 353. Starts writing on the Tr. Exiled by Constantine II in East 356-360. Finishes De Trinitate. The "Athanasius of the West" brings wealth of the East to the West. Only Marius Victorinus' Theological Treatises precede him as a Trinitarian treatise in the West.

Biography: H. received a first-rate education in classical philosophy and rhetoric. He came from a pagan family but converted in early adulthood and was instructed in the Scriptures. He became bishop of Poitiers ca. 350. In 355-56 his life became enmeshed in the Arian controversy as he began to defend the Nicene creed and argue against homoean bishops. Julian (the Apostate, while in the reign of Constantius) therefore exiled him to Asia Minor (Phrygia). It was here that he learned eastern theology, informing his colleagues back in Gaul and Britannia of developments in the eastern part of the Roman Empire. At the Synod of Seleucia, he supported the homoiousian position, but was forced to sign a homoean document at the instigation of Constantius, who was seeking a via media along with Basil of Ancyra to the Arian conflict. When Constantius died, H. returned to Gaul where he pursued his theological agenda, along with Eusebius of Vercelli. In Gaul, H. instituted liturgical singing and also mentored Martin of Tours.

H.'s main exegetical works are the Commentarius in Matthaeum and Tractatus super psalmos, which demonstrate the shift in his theology from the early 350's (the date of the work on Matthew) to the 360's (the supposed date of the work on the Psalms) after his encounter with the theology of the east, especially with Origen. He also wrote polemic works: one against Valentinius and Ursacius and another against Constantius emerging from his frustration after the Council of Seleucia, and against Auxentius the homoean bishop of Milan. He composed a book of hymns(Liber hymnorum) of which only three authentic ones survive. His greatest work, though, is his dogmatic authorship of De Trinitate, written between 356-59. Along with a positive account of the doctrine of the Father, Son, and Holy Spirit, H. also writes against the unorthodox position of Arius and his followers and also Marcellus of Ancyra and Photinus of Sirmium. Some parts of the work could be interpreted as subordinationist, but many parts highlight the unity and equality of Son with Father.

H. was incontrovertibly a man of great learning, which he used in synthesizing eastern and western theology. Besides being a champion of Orthodox theology, he also tried vigorously to show how the homoiousians and the homoousians could be compatible and how they could not be synthesized. Though he did not achieve this completely in his lifetime, those parties largely converged later on. Jerome, Cassiodorus, and Augustine use H.'s teachings in their works. He introduced Origen to the West in his Psalms commentary.