Strategos or Strategus, plural strategoi, (Greek: στρατηγός, pl. στρατηγοί; Doric Greek: στραταγός, stratagos; literally meaning "army leader") is used in Greek to mean military general. In the Hellenistic world and the Byzantine Empire the term was also used to describe a military governor. In the modern Hellenic Army it is the highest officer rank.
In its most famous attestation, in Classical Athens, the office of strategos existed already in the 6th century BC, but it was only with the reforms of Cleisthenes in 501 BC that it assumed its "classical" form: a board of ten strategoi who were elected annually, one from each tribe (phyle). The ten were of equal status, and replaced the polemarchos, who had hitherto been the senior military commander. At Marathon in 490 BC (according to Herodotus) they decided strategy by majority vote, and each held the presidency in daily rotation. At this date the polemarchos had a casting vote, and one view is that he was the commander-in-chief; but from 486 onwards the polemarchos, like the other archontes, was appointed by lot. The annual election of the strategoi was held in the spring, and their term of office coincided with the ordinary Athenian year, from midsummer to midsummer. If a strategos died or was dismissed from office, a by-election might be held to replace him.
The strict adherence to the principle of a strategos from each tribe lasted until c. 440 BC, after which two strategoi could be selected from the same tribe and another tribe be left without its own strategos, perhaps because no suitable candidate might be available. This system continued at least until c. 356/7 BC, but by the time Aristotle wrote his Constitution of the Athenians in c. 330 BC, the appointments were made without any reference to tribal affiliation. Hence, during the Hellenistic period, although the number of the tribes was increased, the number of strategoi remained constant at ten.