(Greek: "military commander, general")
In Ancient Greece, the title strategos (plural: strategoi) applied to all high-level military commanders, in all the Greek poleis, but the term is most frequently applied to the ten members of the Athenian college1 of generals. These were elected for one-year terms.
The Athenian college was founded in 501 BCE, and the strategoi were placed in charge of Athens' army and navy.2 During the 5th century BCE, the strategoi were the most powerful civic officials in Athens, with political leaders and demagogues often doubling in the rôle of strategoi. In the 4th century BCE, these political and military offices were separated, the strategoi mostly being professional military commanders hired for the job.
Note(s):
1 "College" is here used in the sense of a "board" or "commission", rather than in the sense of "place of learning".
2 Often, a strategos would be expected to command both army and navy forces - however, some strategoi specialised as "naval strategoi".