The constellation represents Cepheus, the king of Ethiopia and Cassiopeia’s husband in Greek mythology. Zeus placed him in the sky after his tragic death because he was descended from one of Zeus’ loves, the nymph Io. Cepheus ruled not the modern-day Ethiopia, but the stretch of land between the southeastern Mediterranean and the Red Sea, the area that contains parts of the modern-day Egypt, Israel and Jordan.
Cepheus’ wife Cassiopeia was a very vain woman. Once, she boasted that she was more beautiful than the Nereids (sea nymphs, one of them the wife of the sea god Poseidon), which angered the nymphs and Poseidon, who then sent a sea monster, represented by the constellation Cetus, to ravage Cepheus’ land.