Hesychius of Miletus, Greek chronicler and biographer, surnamed Illustrius, son of an advocate, flourished at Constantinople in the 5th century AD during the reign of Justinian.

According to Photius (cod. 69) he was the author of three important works:

1. A Compendium of Universal History in six books, from Belus, the reputed founder of the Assyrian empire, to Anastasius I (d. 518). A considerable fragment has been preserved from the sixth book, a history of Byzantium from its earliest beginnings till the time of Constantine the Great.
2. A Biographical Dictionary of Learned Men, arranged according to classes (poets, philosophers), the chief sources of which were the works of Aelius Dionysius and of Herennius Philo . Much of it has been incorporated in the lexicon of Suidas, as we learn from that author. It is disputed, however, whether the words in Suidas ("of which this book is an epitome") mean that Suidas himself epitomized the work of Hesychius, or whether they are part of the title of an already epitomized Hesychius used by Suidas. The second view is more generally held. The epitome referred to, in which alphabetical order was substituted for arrangement in classes and some articles on Christian writers added as a concession to the times, is assigned from internal indications to the years 829-837. Both it and the original work are lost, with the exception of the excerpts in Photius and Suidas. A smaller compilation, chiefly from Diogenes Laërtius and Suidas, with a similar title, is the work of an unknown author of the 11th or 12th century.
3. A History of the Reign of Justin I (518—527) and the early years of Justinian, completely lost.

Photius praises the style of Hesychius, and credits him with being a veracious historian.

Editions; JC Orelli (1820) and J Flach (1882); fragments in CW Muller, Frag. hist. Graec. iv. 143 and in T Preger’s Scriptores originis Constantinopolitanae, i. (1901); Pseudo-Hesychius, by J Flach (1880); see generally K Krumbacher, Geschichte der byzantinischen Literatur (1897).