Kea has been inhabited since prehistoric times, as attested by the fortified settlement of Agia Irini, one of the most important centers in the Aegean during the Bronze Age (3rd–2nd millennium BC), with close ties to Minoan Crete and the Cyclades. Its sanctuary with life-sized clay female figurines remains unique in the Greek world.
In antiquity the island was divided into four city-states — Ioulida, Karthaia, Korissia and Poiessa — which flourished and took part in the Athenian Alliance. Kea gave birth to great intellectual figures: the lyric poets Simonides and Bacchylides, the sophist Prodicus and the physician Erasistratus. The carving of the legendary Lion is also dated to this period.
After the Roman and Byzantine eras, during which churches such as Panagia Episkopi were built, the island passed to the Venetians after the Fourth Crusade (1204) and was incorporated into the sphere of the Duchy of the Aegean. Ioulida was fortified with a medieval castle on the ancient acropolis, while pirate raids marked life along the coasts.
The island passed to the Ottoman Empire and in the following centuries developed a strong maritime and trading tradition, thanks to its proximity to Attica. It was incorporated into the Greek state after the 1821 Revolution, when the neoclassical buildings of Ioulida were also built. In modern times Kea, with its rural tradition, its oak forests and its trails, has become a favorite destination for hiking and quiet holidays near Athens.