The Neoplatonist order of study of the works of Aristotle   and Plato was designed to lead people up to God, starting from Aristotle’s logic and finishing with Plato. There were two Plato cycles, as described in the Anonymous Prolegomena, one culminating in Plato’s Philebus   on the Good, and one consisting of his Timaeus   on the divine Intellect, and his Parmenides   on the One. The order of study and the peculiar views on the supposed single aim of each Platonic dialogue, are said to have been established by Iamblichus  .

As for the earlier part of the course, there was much disagreement on the right order for ethics, mathematics and physics, on which see e.g. Olympiodorus   Prolegomena 8,29-9,12, and Ammonius   in Isag. 12,20-13,7. On one view, a preliminary non-Aristotelian ethics was needed, because (Ammonius in Cat. 5,31-6,9; Simplicius   in Cat. 5,3-6,5) Aristotle’s ethics presupposed logic. Hence we have Simplicius’ commentary on Epictetus  , but the only extant commentaries on Aristotle’s ethics up to 600 AD are not by Neoplatonists (Porphyry  ’s is lost). The reading of Aristotle would then start with the logical works, prefaced by Porphyry’s Isagoge (Introduction). After that came Aristotle’s ethics (if it was read), physics, and then his theology, with mathematics sometimes as a preliminary to the whole sequence and sometimes coming late as a bridge from physics to theology, as recommended below by Ammonius, who gives a fuller rationale in in Isag. 12,20-13,7. [SorabjiPC3  :41]