During the Middle Platonic period, from the second-century CE on, and in a more elaborately structured way from the time of Iamblichus (early fourth-century CE) on, the Platonist Schools of later antiquity took their students through a fixed sequence of Platonic dialogues, beginning with the Alcibiades I, concerned as it was with the theme of self-knowledge, and ending--at least in the later period--with the Timaeus and Parmenides, representing the two 'pinnacles' of Platonic philosophy, concerned with the physical and intelligible realms, respectively. There seems also have been a preliminary period of study, in which one mastered the techniques of logic, with the help of Aristotle's Organon. It may be also that, at least in Iamblichus' school and later, some attention was paid to the life and teachings of Pythagoras, including Pythagorean mathematics and numerology, and perhaps a degree of observance of the Pythagorean way of life, e.g. periods of silence, meditation, dietary restrictions.