Clytus (or Cleitarchus) was a Greek historian of the 4th century BCE, primarily known as an early historian of Alexander the Great. He was the son of the historian Deinon of Colophon. Though some ancient sources like Quintilian doubted his presence on the campaigns, he is said to have accompanied Alexander, and his work was produced in the early Hellenistic period following the king’s death [1]. Details of his life are obscure, reconstructed from later references; the Byzantine Suda calls him a writer on Alexander from Alexandria, though this may indicate his later reputation rather than his origin [1].

His major work was the History of Alexander (Ἱστορίαι Ἀλεξάνδρου or Περὶ Ἀλεξάνδρου), a multi-volume account now lost but preserved in fragments and testimonia by later authors such as Diodorus Siculus, Curtius Rufus, and Plutarch [1][2].

Clytus holds significant though controversial importance as a source. His history was immensely popular in antiquity, characterized by a vivid and sensationalist style [1][2]. Despite criticism from contemporaries like Ptolemy and Aristobulus for inaccuracy and exaggeration, his narrative fundamentally shaped the "Vulgate" tradition of Alexander historiography, influencing Diodorus, Curtius, and Justin, and serving as a primary conduit for the Alexander legend [1].

Sources 1. Oxford Research Encyclopedia of Classics (Oxford University Press): https://oxfordre.com/classics/view/10.1093/acrefore/9780199381135.001.0001/acrefore-9780199381135-e-1682 2. Perseus Digital Library (Tufts University): http://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0062:entry=cleitarchus-harpers