c. 460–400 BC · Ancient Greece

Athenian general and historian of the war between Athens and Sparta. Exiled after a military failure, he wrote the History of the Peloponnesian War as a possession for all time — a rigorous, unsparing account of power, empire, and human nature under the pressure of war.
Bust of Thucydides — Roman copy of an early 4th-century BC Greek original, Royal Ontario Museum — public domain, via Wikimedia Commons