In Greek mythology, Ceyx (/ˈsiːɪks/; Ancient Greek: Κήϋξ, translit. Kēüx) was a king of Trachis in Thessaly. He received Heracles, and Heracles's sons later fled to him. Some accounts make him Amphitryon's nephew, with Heracles building Trachis for him. Muller supposes that the marriage of Ceyx and his connection with Heracles were the subjects of ancient poems. Ceyx befriended Heracles and offered him protection against King Eurystheus. Ceyx's son Hippasus accompanied Heracles on his campaign against King Eurytus of Oechalia, during which Hippasus was slain in battle. Ceyx was also called the father of Hylas and Themistonoe, who married King Cycnus