Baring-Gould’s sources: In the Roman Missal, before 1435, there was no mention of S. Hilary; in the reformed Breviary of Cardinal Quignon, published by authority of Pope Paul III., S. Hilary was commemorated on Jan. 31st, the same day as that on which he was noted in the York Calendar, because Jan. 13th is the Octave of the Epiphany. Afterwards, however, the commemoration of S. Hilary was fixed for Jan. 14th, his name being inserted in the Martyrology on the 13th; but with this clause, "His festival is, however, to be celebrated on the morrow," so as not to interfere with the Octave of the Epiphany. The Sarum, Dominican, Belgian, and some of the German Calendars mark the 13th as the feast of S. Hilary. The Anglican Calendar also notes his name on this day. The Bollandists give his life on this day, though in the Roman offices the commemoration is on the morrow. His own writings, and the histories of his age, contain all the materials for his life.
S. Hilary was born at Poictiers in Gaul [roughly modern France and Belgium]. There is some reason to believe that his family was illustrious in that country. His parents were pagans, and he was brought up in idolatry. He gives an account of his conversion to the faith of Christ in his book "On the Trinity." He was married before his conversion; and his wife, by whom he had a daughter, named Apra, was yet living when he was chosen Bishop of Poictiers, about the year 353; but from the time of his ordination he lived in perpetual continence. It is probable that S. Hilary was elected Bishop from the rank of a layman, as was often the case in the early ages, and received all orders by accumulation. He soon became renowned in Gaul as a preacher; and S. Martin [St. Martin of Tours (d. 397), soldier turned bishop], then a young man, was attracted by his name, and lived for a time at Poictiers as his disciple.
Immediately after the Arian [followers of Arius, who taught that the Son is a created being, not fully God] Council at Milan, in a.d. 355, which had condemned S. Athanasius [bishop of Alexandria (d. 373), great defender of the Nicene faith], and had prevailed on the Emperor Constantius to banish all the Bishops who adhered to him, S. Hilary wrote to the Emperor, entreating him to stop the persecution, to recall the Catholic Bishops, and forbid secular judges to interfere in the affairs of the Church. This remonstrance had no effect; but he had the satisfaction of seeing the Gallican Bishops remain firm during those days of trial. Saturninus, Bishop of Arles, alone united with Ursacius and Valens, two Illyrian Bishops, to vex the Catholics. They held an Arian synod at Béziers in Languedoc, at which Saturninus himself presided. S. Hilary there made a noble confession of the Nicene Faith, and refuted the heresy of Arius; but the party of Saturninus, reinforced by Bishops from the neighbouring countries, was too strong for him, and he was condemned and deposed; and immediately afterwards the Emperor Constantius banished him into Phrygia. He left Gaul early in a.d. 356, in company with Rhodanus, Bishop of Toulouse, whom God called from those evils to His kingdom, soon after their arrival in Phrygia.
His departure was followed by a cruel persecution of the Gallican clergy; but nothing could daunt their constancy, or prevail on them to communicate with the enemies of S. Hilary and the Nicene Faith, or to fill up his see, which in the eye of the Church was not vacant. The priests and deacons of Toulouse were severely beaten, and their church profaned. In a.d. 357 the Bishops wrote a letter to S. Hilary assuring him of their fidelity and firmness. About the same time S. Hilary received a letter from Apra, his only daughter, informing him that she had been asked in marriage by a young man. She was then about thirteen or fourteen years of age. He immediately wrote to her, entreating her to set her thoughts on the more precious rewards which the Lord Jesus has promised to those virgins who devote themselves wholly to their Heavenly Spouse, and are not entangled in the snares of earthly love. He reminded her of that blissful company whom the Church commemorates on the feast of the Holy Innocents (Dec. 28), who sing a new song which no man can learn but they who are virgins and follow the Lamb whithersoever He goeth. She yielded to his pious counsel; and on his return home God took her to Himself at his request, without pain or any visible sickness. Bishop Jeremy Taylor relates this little story in his own beautiful language in the "Holy Dying."
In return for the comforting letter which the Gallican Bishops had sent him, and at their request to be informed regarding the faith of the Eastern Churches, S. Hilary wrote his "History of Synods" in the end of a.d. 358. It contains an account of the various councils that had been assembled in the East on the subject of the Arian heresy, together with a defence of the Nicene Faith. It is addressed to the British Bishops among others, whom he congratulates on their steadfastness. The Saint also wrote his book "On the Trinity" during his exile, and a smaller treatise "Against the Arians." He was also the undoubted author of several hymns, and others have been attributed to him.
In a.d. 359 the Western Bishops held a synod at Rimini, at which nearly four hundred were present. The Arian party among them beguiled the rest by its address, to sanction its errors by their signatures. The Bishops of Agen and Tongres took a prominent lead in the proceedings of the synod. In September of the same year S. Hilary was invited with other Catholic Bishops by the semi-Arians to their council at Seleucia, in Isauria. Their object was to defeat the Arians, and they hoped that the Catholics would assist them. In this council S. Hilary bore witness to the faith of the Western Church being the same as that declared to be the Catholic Faith at the Council of Nice in a.d. 325, and he protested against both the Arian and semi-Arian opinions as novelties. He accompanied the deputies of the council to Constantinople, in hopes of obtaining from the Emperor Constantius the recall of his sentence of banishment.
While the Arian synod was sitting at Constantinople, in January, a.d. 360, he entreated the Emperor to grant him a conference with Saturninus, Bishop of Arles, the author of his exile, and that he might be allowed to appear in the synod, and bear witness to the Catholic Faith. He also complained of the perplexity which the multiplication of creeds and confessions of faith had occasioned; for in the preceding year alone four had been published to the Church. The Emperor refused to grant S. Hilary what he asked; but the Arians so much dreaded his presence in the East, that they persuaded Constantius to send him back to Gaul, yet without formally recalling the sentence of exile.
The joy of his return to his Church and his native land was much lessened by the miserable confusion which he left behind him in the East. Still it must have been very great; and his approach was hailed with delight by the Church in Gaul. S. Martin, who had been living in retirement in the island of Gallenari, off the city of Genoa, went to Rome to meet him; but finding that he had already left it, he followed him to Poictiers, and soon after built a monastery near the town (see November 11.) S. Hilary immediately applied himself to repair the mischief which the Council of Rimini had done: and a synod was assembled at Paris, which condemned its proceedings, and declared the true Faith of the consubstantiality of the Son of God. The Bishops also corresponded with their banished brethren in the East.
In a.d. 363 S. Hilary made a journey into Italy in company with Eusebius of Vercelli. They were at Milan in the autumn of the following year, at the time when the Emperor Valentinian arrived there. The people were Catholic, and even abstained from entering the churches, to avoid communicating with Auxentius their Arian Bishop. In a public disputation which the Emperor invited him to hold, S. Hilary extorted from the Arian a confession of the Nicene Faith, which was taken down in writing and preserved. Auxentius was enraged at being thus vanquished, and prevailed on the Emperor to send S. Hilary away from Milan. Before his departure he addressed a letter to the Catholic Bishops and laity in the neighbourhood, exhorting them to remain firm. This was the last public act of his life which is recorded. He returned home to Poictiers, and finished his labours by a blessed death in January, a.d. 368, according to the testimony of the greater number of historians. A brilliant light is said to have filled the chamber where the body of the holy man was lying. S. Gregory of Tours [bishop and historian of the Franks (d. 594)] attests the truth of a miracle performed at his tomb; and others also are authenticated by various writers. But neither the fame of these, nor respect for the memory of the saintly Confessor, prevented his tomb from being violated by the Calvinists in 1567.