(9th century) Irish teacher, theologian, philosopher, and poet. He was head of the palace school under Charles the Bald (c.847), and acquired prominence in the world of letters through his translation of the works of Pseudo-Dionysius. In addition he wrote commentaries on the Gospel of Saint John and on the works of Pseudo-Dionysius, a work on predestination and probably one on the Eucharist, a philosophical work on the division of nature, a treatise on the soul, and Isome poems. Although the errors into which he fell were many and serious, there can be no doubt that he abhorred heresy and that he always regarded himself as a loyal son of the Church.