Dorieus' Expedition to Sicily (c.510 BC) was an unsuccessful attempt by a band of Greek adventurers to capture the town of Eryx in western Sicily and use it as the basis of a new Greek city.
Dorieus was a member of the Spartan royal family, a younger son of Cleomenes, king from c.520 BC and the brother of King Leonidas of Thermopylae fame. A few years after his father came to the throne Dorieus decided to seek his fortune overseas. His first venture, in c.514, was to North Africa, where he attempted to found a colony between the Persian and Carthaginian Empires. He was expelled by the Carthaginians and Libyans, and returned to Greece where he consulted the oracles.
They told him to 'found Heraclea in Sicily', which he interpreted as an instruction to found a city in western Sicily. Dorieus's new target was the town of Eryx, an Elymian settlement on the north-west coast of Sicily, between the Phoenician cities of Motya and Panormus. According to legend this town had been conquered by Hercules during one of his labours, but then returned to its inhabitants until one of his descendants came to claim it. As a member of the Spartan royal house Dorieus could claim descent from Hercules.
Dorieus gathered a band of adventurers, including four other Spartans, who would join him as co-founders of the new settlement. They departed for Sicily in about 510 BC, and after taking part in some fighting in southern Italy soon reached their target.
After that the expedition was a total disaster. Dorieus and his band may have held Eryx for long enough to rename it Heraclea, but they were quickly defeated by an alliance of Phoenicians and Elymians. Dorieus was killed and most of his army destroyed.
Only one of the fire Spartan 'co-founders', Euryleon, survived the disaster. He took his surviving men and captured a nearby Greek settlement at Minoa. His army then moved south and helped the inhabitants of Selinus overthrow Peithagoras, their tyrant. Euryleon then threatened to become a tyrant himself and was killed.
Dorieus' death was later used by Gelon, tyrant of Syracuse in the 480s in an attempt to gain support from mainland Greece for his attempted conquests, but without much success.