THEODORUS THE READER — so called from his office as reader in the church of Hagia Sophia in Constantinople, lived in the 6th century.
He was the author of an epitome of the historical works of Socrates, Sozomen, and Theodoret, commonly called the *Historia tripartita*, upon which the first and the beginning of the second book of Cassiodorus’s *Historia ecclesiastica tripartita* depend. Theodorus’s second work is a continuation of the *Historia tripartita* (in 2.1), covering the years 450 to 527. While the *Historia tripartita* itself has never been published, the text of the second work is lost. An epitome of this second work, also lost, served as a source for later historians, especially Theophanes the Confessor (d. 817). Theodorus’s work was based on a chronicle by Eustathius of Epiphania (in Syria) and the ecclesiastical history of the Monophysite John Diacrinomenus.