Cephalus is an Ancient Greek name, used both for historical persons and for characters in Greek mythology. The word cephalus is Greek for "head", perhaps used here because Cephalus was the founding "head" of a great family that includes Odysseus.
The first Cephalus was an Athenian, son of Hermes and Herse. When Hermes fell in love with Herse, a jealous Aglaulus, Herse's sister, stood between them and refused to move. Hermes changed her to stone.
The other Cephalus was an Aeolian, the son of Deioneus (or Deion), ruler of Phocis, and Diomede, and grandson of Aeolus. Cephalus was married to Procris, a daughter of Erechtheus. The goddess Eos, of dawn (Aurora at Rome) kidnapped Cephalus when he was hunting. Cephalus and Eos became lovers, and she bore him a son named Phaëthon (not to be confused with the son of the sun-god Helios). Some sources also give Tithonos and Hesperus as children of Cephalus and Eos. However, after some years, Cephalus began pining for Procris, causing a disgruntled Eos to return him to her - and put a curse on them.
Procris had come into possession of a magical javelin, given by Diana that never missed its target, as well as a hunting hound (named Laelaps) that always caught its prey. The hound met its end chasing a fox (the Teumessian vixen) which could not be caught; both fox and the hound were turned into stone. But the javelin continued to be used by Cephalus, who was an avid hunter.
Although Cephalus and Procris were reconciled, Procris remained suspicious. Cephalus sat by a tree one day, hot after hunting, and sang a little hymn to the wind (Aura). A passerby heard him and thought he was serenading a lover. Procris found out and the next day went out to find him. As he sat singing the same hymn, she thought he was singing to his ex-lover Eos (Aurora) and moved. Cephalus, hearing a stirring in the brush and thinking the noise came from an animal, threw the never-erring javelin in the direction of the sound - and Procris was impaled. As she lay dying in his arms, she told him "On our wedding vows, please never marry Eos". Cephalus was distraught at the death of his beloved Procris, and went into exile. (For different versions of this story, see Procris.) Later, Cephalus helped Amphitryon of Mycenae in a war against the Taphians and Teleboans. He was awarded with the island of Samos, which thereafter came to be known as Cephallenia. The people who lived on Cephallenia and nearby islands came to be known as Cephallenians.
Cephalus eventually married again, choosing a daughter of Minyas to be his wife. This woman (named Clymene, according to some sources) bore him a son named Arcesius. Arceisius succeeded Cephalus as ruler of his Cephallenian realm. This Arceisius was the grandfather of Odysseus, son of Laertes. Nevertheless, Cephalus never forgave himself over the death of Procris, and he committed suicide by leaping from Cape Leucas into the sea.
The legend is retold in Cephalus and Procris; Narcissus, a 1595 poem by Thomas Edwards. It is echoed in Shakespeare's Midsummer Night's Dream (Act V, scene i), where Pyramus and Thisbe refer to "Shafalus" and "Procrus." While Milton's "the Attic boy" in Il Penseroso is also a reference to Cephalus.
Operatic treatments include Caccini's Il rapimento di Cefalo (c. 1600), Gretry's Céphale et Procris (1773), and Ernst Krenek's Cefalo e Procri (1934), as well as works by Hidalgo (1660), Elisabeth Jacquet de la Guerre (1694), Krieger and others.