Deiochus the Historian (Δηίοχος ὁ Ἱστορικός) was a minor Greek historian of the 4th century BCE. No details of his life survive. He is known only through later references, primarily in the Bibliotheca of the Byzantine patriarch Photius (c. 810–893 CE), who groups him with historians of uncertain reliability [1]. The 10th-century Byzantine encyclopedia Suda also provides an entry [2].

He is credited with two lost historical works: the Persika (Περσικά), a history of Persia in at least two books, and the Libyka (Λιβυκά), a history of Libya in at least four books [1, 2]. Photius notes the Libyka began with mythological origins [1]. The fragments indicate his writing blended historical and mythological material.

Deiochus is a figure of minimal significance, emblematic of many lost local historians. His importance lies solely in being a named source for later compilers; his fragments may preserve traces of lost traditions about Persia and Libya. Photius treated his reliability with skepticism [1].

Sources 1. Photius, Bibliotheca, Codex 161. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A2008.01.0450%3Atext%3D161 2. Suda Online, entry Delta 210. https://www.cs.uky.edu/~raphael/sol/sol-entries/delta/210 3. Smith's Dictionary of Greek and Roman Biography and Mythology, Vol. 1, p. 951. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0104%3Aentry%3Ddeiochus-bio-1