This Introduction and the chronological table that follows it are intended to give readers who may not be familiar with this period of Peripatetic philosophy a guide to the major trends and developments, and to introduce some of the philosophers who will be considered in the following pages. The actual ancient evidence relating to some of the identifications and dates will be found below in Chapter 1, ‘People’.

Aristotle’s school, the Lyceum, has been regarded both in antiquity and by modern scholars as entering a period of decline after its third head, Strato. This impression may in part be the result of tendentious representation in the ancient evidence, but in so far as it is accurate, the fundamental reason for the decline seems to be, not that Aristotle’s works were no longer available (below, 2), but that the Lyceum had never had an agenda that was philosophical in the narrow sense of that term predominant in antiquity, as promoting a way of life and an attitude towards its events. From Aristotle himself onwards, the concern of the school had largely been with the collecting and analysis of information on a wide range of topics, and it thus suffered from the double disadvantage that, on the one hand, it did not have such a clear evangelical message to propound as did the Epicureans or the Stoics (for the message of Nicomachean Ethics 10, that the highest human activity is theoretical study for its own sake, was probably of no wider appeal in antiquity than it is now), and, on the other, that such research was being carried on elsewhere, above all in Ptolemaic Alexandria. The notion of Aristotelianism as a distinctive philosophical system, in a sense closer to modern understandings of ‘philosophical’, is in no small part the result of a process that had its beginnings in the period considered in the present book.