It has been strongly disputed that Philoponus is the author of the commentary on the third book of De Anima printed in vol. xv of CAG under his name, and Stephanus of Alexandria has been taken to be its real author. The evidence for the authorship of Stephanus is as follows: (I) Codex Parisinus gr. 1914, written in the twelfth century, has an adscript by a later hand saying βιβλ⋯ον τρ⋯τον ⋯π⋯ ϕωνης στεϕ⋯νου (‘third book from the voice of Stephanus’), and the same appears in the fifteenth-century Codex Estensis iii F 8. (II) In 543.9 there is a clause saying ὡς ⋯ν τῷ περ⋯ ⋯ρμηνε⋯ας ⋯μ⋯θομεν (‘as we learnt in the De Interpretatione’), which was taken by M. Hayduck to be direct reference to Stephanus' commentary on the De Interpretatione, edited also by Hayduck in vol. xiii/3 of CAG. (III) The third book, says Hayduck, is short (brevis) and jejune (jejunus), in contrast to the verbosity of the preceding two books. (IV) The commentary on the third book of De Anima is divided into lectures (πρ⋯ξεις), but the first two books are not. (V) Some locutions are used constantly in the third book and in Stephanus' in De Interpretatione as well. (VI) In the Codex Vaticanus gr. 241 fol. 6 (fourteenth century) we are told that Stephanus also wrote a commentary on the De Anima.