Istros the Callimachean (Ἴστρος ὁ Καλλιμάχειος) was a Hellenistic historian and scholar of the 3rd century BCE. He was a pupil of the poet Callimachus at the Library of Alexandria, from which his epithet derives [1]. His floruit is placed in the mid-3rd century BCE, and he is often distinguished from a later historian from the city of Istria [1][2].

His prolific output survives only in fragments. Attributed works include the Collection of Attic Myths (or Attika), Argolica, Cretica, On the Colonisation of Elis, On the Games, On the Sacrifices among the Athenians, and On the Poetical Compositions of Sophocles, alongside histories of Macedonia, Syria, and Piraeus [1]. His fragments are collected in Die Fragmente der griechischen Historiker (FGrHist 334) [2].

Istros exemplifies the antiquarian historiography of the Alexandrian library. His compilations of local myth, history, and cult practice were key sources for later lexicographers like Harpocration and Athenaeus [1][2]. His work provides valuable insight into regional Greek traditions and early scholarly methods.

Sources 1. Encyclopædia Britannica: https://www.britannica.com/biography/Istros 2. Perseus Digital Library, entry for "Istros" in Smith's Dictionary of Greek and Roman Biography and Mythology: http://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0104:entry=istros-bio-2