In Greek myth, the god Apollo was the son of Zeus and Leto, and twin brother of Artemis. The most characteristically Greek of all the gods, he embodied youthful but mature male beauty and moral excellence, and was associated especially with the beneficent aspects of civilization, giving to Greek culture its ideal of the beautiful, athletic, virtuous, and cultivated young man. Apollo was the god of plague but also of healing, of music (especially the Iyre), archery (but not war, nor hunting), and prophecy; the god also of light (whence his epithet Phoebus, 'the bright'), sometimes identified with the sun. He was also associated with the care of flocks and herds, hence the epithet Nomios, 'of the pastures'. There is no certain occurrence of his name in the Linear B tablets.

Apollo's first feat was to seize Delphi for his abode; in doing so he destroyed the dragon Python, its guardian deity who personified the dark forces of the Underworld, an act he had to expiate by exile and purification. His 'fusion' with this earlier deity explains his title Apollo Pythios, 'Pythian Apollo'. Of his many loves, the most famous was that for Coronis, mother of Asclepius. Others loved by Apollo include Cassandra, the Cumaean Sibyl, Cyrene, Daphne, Hyacinthus, and Marpessa.

Apollo was not worshipped at Delphi before the eighth century BCE. His origins are uncertain, but it is believed that he came either from somewhere north of Greece or from Asia. One of his most common epithets is Lykeios, and Homer's lliad connects him with Lycia. Moreover, in that epic he is an enemy of the Greeks. There are also many oracles of Apollo in Asia Minor. But his Asian origin remains unproved. How and why he became a prophetic god in Greece is not known, but he is so from the earliest records. Delphi was the most important of his oracular shrines but those in lonia at Branchidae and Claros were notable, and he had a famous shrinc on the holy island of Oelos. All Greece worshipped him and respected him. Apart from favouring Troy in the lliad, Apollo was usually impartial in politics.

Notable departures from impartiality occurred when the Delphic Oracle began by supporting the Persians in the Persian Wars, and when it supported Sparta in the Peloponnesian War. The Homeric Hymns to the Delian and the Pythian Apollo relate the story of his birth and of the founding of his Pythian temple. The paean was traditionally sung to him.

In Roman religton. Apollo was introduced early into Italy, partly through Etruria and partly through the Greek settlements in Magna Graecia, but he was never properly identified with a Roman god. He was first introduced as a god of healing, but soon became prominent as a god of oracles and prophecy. In Virgil he figures in both these characters, but especially as the giver of oracles; the Cumaean Sibyl was his priestess. In Virgil's Eclogues, Apollo appears also as the patron of poetry and music. The oldest temple to him in Rome was erected in 432 BC. His cult was further developed by the emperor Augustus, who took him as his special patron and erected to him a great temple on the Palatinc.