Nicholas II of Saint Omer was the lord of half of Thebes in Frankish Greece from 1258 to his death in 1294. From his two marriages he became one of the richest and most powerful barons of his time, building a splendid castle at Thebes as well as the Old Navarino castle. He also served as bailli of the Principality of Achaea on behalf of the Angevins of Naples between 1287 and 1289.