Pelagon was a king of Phocis who had rich herds of cows. One of these led Cadmus to the place where he was to found a city. This was Cadmeia, later to become Thebes in Boeotia (significantly 'Cowland', from bous, 'cow').

Pelagon's name immediately suggests 'sea' (pelagos), but it has also been understood as pelogonos, meaning 'born from clay' (pelos, 'clay', 'mud' and gone, 'offspring'). Both these are possibilities for one who lived in a 'sea' region (Phocis bordered the Gulf of Corinth to the west of Boeotia) and who was originally a 'bumpkin' herdsman, as Pelagon was before he became king.