This article provides edition, translation, and annotation of a Greek excerpt dealing with the christological issue of “whether there is an anhypostatos nature.” Until now unedited and recently catalogued as one of the fragments of Cyril of Alexandria’s Contra Synousiastas, it in fact contains a close parallel to a famous passage from Leontius of Byzantium’s Contra Nestorianos et Eutychianos concerning the distinction between hypostasis and enhypostaton. It is argued that the fragment was written in the aftermath of the Tritheist controversy and, more specifically, that it faces the doctrines of John Philoponus.