in Greek mythology, king of Megara, a son of King Pandion of Athens. His name was given to the Megarian port of Nisaea. Nisus had a purple lock of hair with magic power: if preserved, it would guarantee him life and continued possession of his kingdom. When King Minos of Crete besieged Megara, Nisus' daughter Scylla fell in love with Minos (or, in some accounts, was bribed): she betrayed her city by cutting off her father's purple lock. Nisus was killed (or killed himself) and became transformed into a sea eagle. Scylla later drowned, possibly at the hand of Minos, and was changed into a sea bird (Greek keiris, Latin ciris), possibly a heron, constantly pursued by the sea eagle.