Hiero, allied with Aristodemus, the tyrant of Cumae, leads the Greeks of Campania (now in southern Italy) to defeat their rivals, the Etruscans, in battle near Cumae in 474 in the Bay of Naples.

This victory marks the end of the Etruscan aggression against the Greeks in southern Italy and saves the Greeks of Campania from Etruscan domination.

The Syracusans dedicate a captured Etruscan bronze helmet (now in the British Museum, London), with an inscription commemorating the event, the great panhellenic sanctuary at Olympia.

After their defeat, the Etruscans lose much of their political influence in Italy.

They will soon lose control of the sea and their territories will eventually be taken over by the Romans, Samnites, and Gauls.

The Etruscans will later join the failed Athenian expedition against Syracuse in 415 BCE, which will contribute even further to their decline.