Calcidius (in Latin, it is better written Calcidius than Chalcidius) is known foremost as the author of a rare surviving Latin version of Plato’s Timaeus, and of a partial commentary on the dialogue. He was probably active at the end of the fourth century. We know very little concerning this author, and most of the available information comes from his writings. Thanks to his dedicatory letter, Osio suo Calcidius, which acts as a preface to his version of the Timaeus, we know that this Osius charged him with translating the complex dialogue. Critics do not agree on the identity of this personage: some identify him with the famous Cordoban bishop (ca. 257-357), who played an enormous role in the controversy against the Arian heresy, and others think that he was an imperial functionary with an important post in the court at Milan, active around 395. For his part, Calcidius not only accepted the job, but also took on the task of writing a commentary, given the difficulties of interpreting the original text. There is also a certain consensus that the author and his friend were Christians, even if a careful reading of the commentary reveals the author’s meagre interest in orthodoxy, when there are points of dissension between his militant Platonism and his presumable Christian faith. Certainly he was a man of great learning, who perfectly mastered Greek and Latin.

Calcidius’ philosophical doctrine must have belonged to the neoplatonic school, although some important scholars ascribe him to Medioplatonism, which flourished during the two first centuries of the Christian era, because of certain doctrinal features such as the so-called “Theology of the Three Principles”, that is, God, the form or the Ideas, and matter. This theory was characteristic of the platonic philosophers of the first and second centuries CE, like Arius Didimus, Alcinous, and Apuleius. In any case, it is useful to note the fact that while Calcidius composes a partial commentary on certain points of the doctrine contained in the Timaeus, he prefers to follow the path of the medioplatonic exegetes rather than the systematic exegesis practised by neoplatonists.

It is possible to identify diverse Greek and Latin sources in Calcidius’ work. We can state that he was not a straightforward compiler, and that he produced an eclectic work, the result of a patient and careful selection process from the materials of a good number of authors and works, and not only from Platonic philosophers.

Finally, Calcidius’ fame and his prominent position in the history of Platonism mainly arise from his notable influence on the Medieval West, where, since intellectuals knew little Greek, his work provided a rare point of access to the Athenian master’s writings. In this sense, his work experienced its greatest florescence during the twelfth century, when it was widely adopted by the school in Chartres, particularly by Bernard de Chartres and Guillaume de Conches. Furthermore, researchers have detected his presence in important Renaissance authors, like Marsilio Ficino. [Cristóbal Macías]