Acontius, in Greek legend, a beautiful youth of the island of Ceos. During the festival of Artemis at Delos, Acontius saw and loved Cydippe, a girl of a rich and noble family. He wrote on an apple the words “I swear to wed Acontius” and threw it at her feet. She picked it up and mechanically read the words aloud, thus binding herself by an oath. Thereafter, although she was betrothed three times, she always fell ill before the wedding took place. The Delphic oracle at last explained the matter, and she married Acontius. The story is found in Ovid, Heroides (Heroines) 20 and 21.