Today is the feast of St. Hilary of Poitiers, Doctor of the Church. Here is his entry in the 2005 Martyrologium Romanum:
Sancti Hilarii, episcopi et Ecclesiae doctoris, qui, ad sedem Pictaviensem in Aquitania evectus, sub Constantio imperatore arianae haeresi addicto scriptis fidem nicaenam de Trinitate ac de Christi divinitate strenue propugnavit, quapropter quadriennium in Phrygiam relegatus est. Commentaria quoque celeberrima in Psalmos necnon Evangelium confecit. … [The feast] of Saint Hilary, bishop and doctor of the Church, who, driven from the see of Poitiers in the Aquitane, under the Emperor Constantius, favorable to the Arian heresy, with written works fought strenuously for the Nicean faith about the Trinity and about the divinity of Christ, on account of which he was banished to Phrygia for a period of four years. He also completed very celebrated commentaries on the psalms and the gospels.