This article gives the first comprehensive overview of the fate of the writings and thought of the Jewish exegete and philosopher Philo of Alexandria in the Byzantine period from 500 to 1500 ce. It sets out the evidence, based primarily on named references in a wide range of Byzantine sources, for the questions (1) who read Philo and wrote about him; (2) what part of his legacy did they utilise; (3) why did they refer to him; (4) and what was their attitude to him as a Jewish author. This article gives the first comprehensive overview of the fate of the writings and thought of the Jewish exegete and philosopher Philo of Alexandria in the Byzantine period from 500 to 1500 ce. It sets out the evidence, based primarily on named references in a wide range of Byzantine sources, for the questions (1) who read Philo and wrote about him; (2) what part of his legacy did they utilise; (3) why did they refer to him; (4) and what was their attitude to him as a Jewish author.