  Diodorus came from Iasos in the eastern Aegean. In terms of affiliation he is regularly spoken of in our sources as a ‘Dialectician’. How distinct this school was from the ‘Megaric’ school is a matter of dispute, and one testimony does speak of a certain ‘Diodorus the Megaric’ (see Denyer 2002), who may well be Diodorus Cronus. But at all events no evidence that we possess associates him in any way with the town of Megara, after which the Megaric school was named. Apart from his birthplace, we hear of him as active at Athens in or around the last decade of the fourth century, and later at Alexandria. These were the two major cultural centres of the age.