THE history of Alexandrian scholarship in the Ptolemaic age may be divided into three main sections: the formative period, from the foundation of the Library to the end of the Librarianship of Eratosthenes; the developed period of Aristophanes of Byzantium and Aristarchus; and the period of decline from the departure of Aristarchus to the end of the dynasty. Before studying these three periods we may note a few essential technical items concerning the surviving tradition relating to scholarly work at the time, which will make certain parts of the subsequent narrative more easily comprehensible.
With a small but still increasing number of exceptions, Alexandrian scholarship, in so far as it relates to the editing of and commenting on authors, survives for us solely in the tradition of the scholiasts. The scholia as we have them are products of late Imperial and Byzantine learning, but they form the end of a long tradition which reaches back to the scholars of the early Ptolemaic period, who are quoted in them time without number, not indeed at first hand, but from some of the authors of compendia, notably Didymus. This learned tradition, though not always continuous,1 is usually reliable, and when our scholia tell us that a particular scholar gave this or that explanation, or rejected this or that reading, there is no reason to doubt them; unfortunately, for the most part they report the judgement, explicit or implicit, of earlier scholars, without recording the reason for it. Normally these references to earlier scholars' works concern two closely-connected classes of work, their editions and their commentaries.2 By 'editions' (ἐκδόσεις or διορθώσεις),3 we are to understand individual copies of the poetical work in question--normally only one copy, and thus not available on the market--in which the editor employed certain critical signs (σημει + ̑α) to indicate that a line thus stigmatized was spurious or suspect in his eyes. The reasons for this athetesis were given in the commentary (ὑπόμνημα). The commentary might contain much beside purely textual criticism, and several scholars apparently produced commentaries without editions, and it is not always possible, faced with a loose and inaccurate terminology, to decide whether a particular critic composed a commentary or an edition or both. It is to be noted that the scholia very often refer not to the text as established by an