Hugo, Ethérien a Tuscan theologian of the 12th century, contemporary of pope Alexander III, to whom he dedicated the principal of his works, lived some time at the court of Constantinople, and was highly esteemed by the emperor Comnenus. On the occasion of his conference with the Greek theologians he wrote his treatise De Haeresibus quas Graeci in Latinos devolvunt, also known under the title of le Imnmortali Deo, libri 3. It is published in the Lyons edition of the Library of the Fathers, vol. 22:col. 1198. The same collection contains also a treatise of Hugo on the State of the Soul separated from the Body. — Dupin, Bibl. des Auteurs eccles. du douzieme siecle; Hoefer, Nouv. Biog. Gen. 25, 448.