  Philoponus’ intellectual career began when he was a pupil of the Neoplatonic philosopher Ammonius, son of Hermias, who had been trained by Proclus at Athens and was head of the school at Alexandria. Some of Philoponus’ commentaries profess to be based on Ammonius’ lectures, but others give more room to Philoponus’ own ideas. Eventually, he transformed the usual format of commentary sympathetic to Aristotle’s views into a discourse of open criticism. In the course of this critique, Philoponus examines and repudiates fundamental Aristotelian-Neoplatonic tenets, most prominently the doctrine of the eternity of the world. His style of philosophical commentary, doggedly disrespectful of authority, as well as the conclusions he drew, antagonized Philoponus’ pagan colleagues. Their fierce enmity may have compelled him to abandon his philosophical career in the 530s; Philoponus never succeeded his teacher Ammonius as head of the school. Apparently he altogether abandoned his philosophical career. In the second half of his life he devoted his considerable energy to the theological debates of his time. Ironically, the orthodox church condemned him posthumously as a heretic (in 680–81) because of his tritheistic interpretation of the trinitarian dogma. Understanding the contested concepts within this debate (i.e. those of person, nature, substance, and hupostasis) in strictly Aristotelian senses, Philoponus was perceived to be enunciating not a single god in three persons (Father, Son, and Spirit), but actually three separate divinities.