Medius or Medeios (Greek: Μήδιος, Mήδειoς), son of Oxythemis, was a native of Larissa in Thessaly, an officer and friend of Alexander the Great, and a senior commander under Antigonus I Monophthalmus.
[1][2] He is first mentioned as commanding a trireme during the descent of the Indus River (Arrian, Indica, 18) in 326 BC, but according to the historian Richard Billows it is likely that he was a member of Alexander the Great's expedition into Asia from the beginning, possibly within the ranks of the Thessalian cavalry.
[1][2] After the death of Alexander, he served under Perdiccas, who in 320 BC sent him as commander of the mercenaries in Aristonous of Pella's expedition to Cyprus.
[2][4] According to the historian Hans Hauben,[5] Medius was probably appointed by Antigonus as the chief admiral of his fleet, a post he kept at least until 304 BC.
[4] His authority is cited by Strabo (XI.530) in a manner that would lead us to conclude he had left some historical work, but we find no further mention of him as a writer.