 This attitude toward the philosophy of Aristotle and Plato was passed from Syrianus to Proclus, and from Proclus to Ammonius (ca 440–520 CE). The commentaries of Ammonius on the Categories, the De Interpretatione, the Prior Analytics, and Porphyry’s Isagoge have come down to us. The last is the earliest extant commentary on the Isagoge. By this time the Isagoge had already established itself as part of the reading curriculum of philosophy, which continued with the Categories, the De Interpretatione and the Prior Analytics. Note, however, that Ammonius did not write his commentaries on the Categories, the Prior Analytics, and perhaps the Isagoge. They were produced by pupils who attended his lectures on Aristotle. (For further information and discussion of his commentaries, see Section 1.2 of the entry on  Ammonius.)  Other commentaries originated in the lecture room as a transcription of the oral exposition delivered by the teacher. The commentaries on the Categories based on the lectures offered by Olympiodorus (ca 495–565 CE) and his pupil Elias (David) have reached us. Philoponus (ca 490–570 CE) edited his own lectures on the Categories. However, the most influential of these later commentaries was the one that Simplicius wrote after 529 CE. Simplicius was a man of vast learning and extraordinary synthetic powers. He was also acutely aware of writing at the end of a long and venerable exegetical tradition. He consciously tried to assimilate and blend together the various strands of this tradition. By so doing he left us the most comprehensive and informative survey of the reception of the Categories in antiquity. At first sight Simplicius may look like a modern scholar. His commentary shows the great care and precision of a thoughtful and dedicated interpreter who is explicating the Categories through a close reading of the text. Yet there is one important difference that must not be overlooked. Simplicius was a Platonist and his exegetical activity was intended to show that Plato and Aristotle were in substantial agreement. Simplicius is adamantly clear on his own exegetical ideal: