Hailing from a very wealthy family, he lived in Miletus, then under Persian rule in the satrapy of Lydia. He was active during the time of the Greco-Persian Wars. After having travelled extensively, he settled in his native city, where he occupied a high position, and devoted his time to the composition of geographical and historical works. When Aristagoras, acting tyrant of Miletus, held a council of leading Ionians at Miletus to organize a revolt against Persian rule, Hecataeus tried in vain to dissuade his countrymen from the undertaking. In 494 BC, when the defeated Ionians were obliged to sue for the terms, he was one of the ambassadors to the Persian satrap Artaphernes, whom he persuaded to restore the constitution of the Ionic cities. Hecataeus is the first known Greek historian and was one of the first classical writers to mention the Celtic and Illyrian people.