Aristagoras of Miletus (d.c.497-6) was Tyrant of Miletus and helped trigger the Ionian Revolt against Persia, before fleeing into exile in Thrace where he was killed in a minor siege.
Aristagoras replaced his father-in-law Histiaeus as Tyrant of Miletus, after Histiaeus fell out of favour with Darius I. According to Herodotus Histiaeus played a part in convincing Aristagoras to revolt against the Persians, before promising to put down the revolt in an attempt to win his freedom.
In 400 BC Aristagoras offered his support to a group of aristocratic exiles from Naxos. He won over Artaphernes, satrap of Lydia, who in turn won the support of Darius I. The Persians provided an army, while the Ionian Greeks raised a fleet of 200 triremes. The expedition set off in 399 BC, but according to Herodotus Aristagoras fell out with the Persian admiral, Megabates, a cousin of Darius I. The Naxians were warned of the upcoming attack and managed to resist a four-month long siege.
The failure of this attack left Aristagoras rather vulnerable to attack. This probably explains why he decided to trigger a revolt of the Ionian Cities. He called a council at Miletus, which decided in favour of war. He then laid down his tyranny, and sent messengers to the Ionian fleet, where many of the other Ionian tyrants were captured and deposed. In the winter of 499 he travelled to mainland Greece, where he attempted to find allies. He was unsuccessful in Sparta, but he did manage to convince Athens and Eretria to provided limited support.
In 498 Aristagoras decided to launch an attack on Sardis, capital of the satrapy of Lydia. He didn't accompany the army, but instead put his brother Charopinus and Hermophantus of Miletus in charge. The army captured Sardis, but the city caught fire, and the attacks retreated back towards the coast. Persian reinforcements then arrived and inflicted a heavy defeat on them near Ephesus.
Darius responded to the revolt by sending armies under three of his son-in-laws to Asia Minor. One of these armies, commanded by Otanes and Artaphrenes, recaptured the cities of Clazomenae in Ionia and Cyme in Aeolis. This unnerved Aristagoras, who decided to flee into exile in Thrace. He presented this to his supporters as an attempt to create a safe haven in case the Persians threatened Miletus. He sailed for Thrace at the head of a band of volunteers, and captured Myrcinus, his original destination. Soon afterwards he was killed while besieging a Thracian town.