Calcidius

The Platonist Calcidius (sometimes less correctly spelt Chalcidius) was the author of a Latin work containing a partial translation of, and partial commentary on, Plato's Timaeus. Although of uncertain date, the doctrinal content of his commentary reflects the thought of the Middle Platonist era (c.50 BC-AD 200). Calcidius' date and place of operation are uncertain, the only clue residing in his dedication of his work to one Osius, who has been taken, following identifications in a number of manuscripts, to be the Bishop of Corduba (AD 256-357) and spiritual advisor of Constantine. This identification has been challenged, mainly on the grounds that Isidore of Seville makes no mention of Calcidius in his enumeration of all the Spanish writers that he knows, but this is not conclusive. It is also true that his language is more consistent with a fifth-century than a fourth-century date, but even this is not conclusive when weighed against considerations of content. The main issue is whether Calcidius is to be regarded as exclusively dependent on Middle Platonist sources or as influenced also by the Timaeus commentary of Porphyry. In fact, there are sufficient indications that, unless Calcidius was being very selective (which does not seem to be his method), he knows nothing of Porphyry. His work seems primarily to be a translation of a number of Middle Platonist or Peripatetic Greek sources (or even of a single such source). Identifiable sources include the second century Peripatetic Adrastus of Aphrodisias, who wrote a commentary on the Timaeus concentrating on the mathematical and 'scientific' aspects, and the Neo-Pythagorean Numenius.