I used to live in a community where I daily passed a Catholic parish named St. Hilary. He was a 4th century saint, born in Poitiers in around 310. Educated in Neo-Platonism, he and his family converted to Christianity, and eventually he was chosen as bishop of the Christians of Poitiers. Once in office, he was embroiled in controversy against Arian theology and soon excommunicated an Arian bishop and his supporters. Unfortunately, Hilary himself was shortly sent into exile. While away from Poitiers, however, he wrote epistles that described the differences between Arian and Athanasian/Nicene theology. In affirming and elucidating what became orthodox trinitarian theology, in works like De Trinitate, Hilary became a significant figure in those debates along with Athanasius, the later Cappadocian Fathers, and others. Returning to Gaul in 361, he continued both his diocese leadership and his theological teachings and controversies. He died in about 367, and in honored on this day in both the Western and Eastern churches.