In 474 BC, Hiero I of Syracuse came to the aid of the Cumaeans, who lived on the mainland opposite Ischia, against the Etruscans and defeated them on the sea. He occupied Ischia and the surrounding Parthenopean islands and left behind a garrison to build a fortress before the city of Ischia itself. This was still extant in the Middle Ages, but the original garrison fled before the eruptions of 470 BC and the island was taken over by Neapolitans. The Romans seized Ischia (and Naples) in 322 BC.