The Greek Life of St. Leo of Catania (BHG 981b) is an unusual piece of hagiography, equally distributed between the depiction of the deeds of the Saint and the antics of his rival, the magician Heliodorus, who in some respects foreshadows the character of Dr. Faust. This elegant work could possibly emanate from the Iconophile circles of Constantinople, written towards the end of the Second Iconoclasm (c. 838-842) against the Iconoclast Patriarch John VII, the Grammarian, whose alias is suggested to be the magician Heliodorus. The volume includes a thorough investigation of the manuscript tradition, a critical edition, and an English translation (by Prof. Susan Wessel) of the text ; in the Commentary emphasis is placed on the parallel sources and the material found in the Greek magical papyri that underlies most of the magical stories of Heliodorus, stories which appear for the first time in European literature and resurface four centuries later in Western European tales about Virgil the Necromancer. The Appendix includes the critical edition and annotated translation of the Laudatio Leonis ep. Cataniae (BHG 981d).