Heliodorus of Alexandria and the Anonymous Commentary to Ptolemy’s Tetrabiblos

Abstract

The Anonymous Commentary to Ptolemy’s Tetrabiblos (Anon. in Ptol.) contains a horoscope (Wolf, p. 98) which can be dated AD 448 June 25, in lower Egypt. Other traces of astronomical character provided by the master of the Anonymous in his commentary to Tetr. 2.10 (p. 76, ll. 16-29 Wolf) allow the composition of Anon. in Ptol. to be set between AD 467 and 575ca. On the other hand, the dating between the 5th and 6th centuries, as well as the location of the horoscope in the middle of the 5th century in Alexandria and its environment, are consistent with the close stylistic and structural similarities that any reader of Anon. in Ptol. can notice between this work and the commentaries to Plato and Aristotle which were composed by Ammonius and his disciples in the Neoplatonic school of Alexandria from 470ca. onward. In this paper, we are presenting some evidence that plausibly suggests the hypothesis that the master of the anonymous commentator, whose account in Book 2 has allowed us to set the chronology of Anon. in Ptol., is no other than Heliodorus of Alexandria, the younger brother of the Neoplatonic philosopher Ammonius.