Auxilius a French theologian, concerning whom nothing is known but his works, and that he lived about 894. He wrote De Ordinationibus Formosi Papce, seu Contra Intestinam Discordiam R. Ecclesice, first published by John Morinus, at the end of his work on ordinations (Paris, 1655; Antwerp, 1694); also contained in Bibl. Patrum, i, 7. Auxilius had been ordained by Formosus, and in this work defends the validity of his ordinations.
Mabillon, in his Analecta (ed. Paris, 1723), p. 28, gives another work by this author-viz. a Dialogue on the Matter of Formosus. See Cave, Hist. of Lit. ii, 68; Dupin, Hist. of Eccl. Writers, ii, 128.