Cepheus, King of Aethiopia in the context of "Achiroe"

In Greek mythology, Io (/ˈaɪ.oʊ/; Ancient Greek: Ἰώ [iːɔ̌ː]) was one of the mortal lovers of Zeus. An Argive princess, she was an ancestor of many kings and heroes, such as Perseus, Cadmus, Heracles, Minos, Lynceus, Cepheus, and Danaus. The astronomer Simon Marius named a moon of Jupiter after Io in 1614.

Because her brother was Phoroneus, Io is also known as Phoronis (an adjective form of Phoroneus: "Phoronean"). She was sometimes compared to the Egyptian goddess Isis, whereas her Egyptian husband Telegonus was Osiris.

In Greek mythology, Phineus (/ˈfɪniəs, ˈfɪn.juːs/; Ancient Greek: Φινεύς, Ancient: [pʰiːněws]) was a son of Belus by Anchinoe and thus brother to Aegyptus, Danaus and Cepheus.

Cepheus is a constellation in the deep northern sky, named after Cepheus, a king of Aethiopia in Greek mythology. It is one of the 48 constellations listed by the second century astronomer Ptolemy, and it remains one of the 88 constellations in the modern times.

The constellation's brightest star is Alderamin (Alpha Cephei), with an apparent magnitude of 2.5. Delta Cephei is the prototype of an important class of star known as a Cepheid variable. RW Cephei, an orange hypergiant, together with the red supergiants Mu Cephei, MY Cephei, VV Cephei, V381 Cephei, and V354 Cephei are among the largest stars known. In addition, Cepheus also has the hyperluminous quasar S5 0014+81, which hosts an ultramassive black hole in its core, reported at 40 billion solar masses, about 10,000 times more massive than the central black hole of the Milky Way, making this among the most massive black holes currently known.

In Greek mythology, Idas (/ˈiːdəs/, Ancient Greek: Ἴδας, translit. Ídas) may refer to the following individuals:

• Idas, son of Aphareus
• Idas, one of the Dactyls.
• Idas, an Egyptian prince as son of Aegyptus and Hephaestine. He married Hippodice, daughter of Danaus who killed him during their wedding night.
• Idas, one of the Ethiopian Chiefs, was in the court of Cepheus when the fight broke between Perseus and Phineus. He kept neutral, but was nevertheless accidentally killed by Phineus.
• Idas, son of Clymenus and Epicaste, brother of Harpalyce and Therager.
• Idas, an Athenian son of Arcas and one of the Sacrificial victims of the Minotaur.
• Idas, an Elean from Pisa who participated in the foot-race at Opheltes' funeral games. During the war of the Seven against Thebes he came in succour of Hippomedon, one of the Seven.
• Idas, a man from Onchestus. He was a defender of Thebes in war of the Seven against Thebes and was slain by Tydeus.

• Idas, one of those comrades of Diomedes in Italy who turned into birds.
• Idas, one of the soldiers of Aeneas in Italy. He was killed by Turnus, the man who opposed Aeneas in Italy.

Corythus is the name of six mortal men in Greek mythology.

• Corythus, son of Marmarus, and one of the court of Cepheus. He wounded Pelates during the battle at the wedding feast of Perseus and Andromeda.
• Corythus, an Italian king and father, in some sources, of Iasion and Dardanus by Electra.
• Corythus, one of the Lapiths. Only a youth, he was killed nonetheless by Rhoetus, one of the Centaurs.
• Corythus, an Iberian, beloved of Heracles. Was said to have been the first to devise a helmet (Greek korys, gen. korythos), which took its name from him.
• Corythus, one of the Doliones. He was killed by Tydeus.
• Corythus, a king who raised Telephus, son of Heracles and Auge, as his own son.
• Corythus, son of Paris and the nymph Oenone. When he grew up he went at Troy, where he was received warmly by Helen of Troy and fell in love with her, so Paris killed him. Corythus was alternatively the son of Helen and Paris, who died along with his two brothers when a roof collapsed in Troy.