With the help of Poseidon, Leto arrived in Delos, a floating island that was not part of the earth Hera had forbidden Leto to bear her children. Clinging to an Olive Tree, Leto gave birth, first to Artemis. Nine days later Apollo emerged with the help of his twin sister’s midwifery skills.
As a baby, Apollo is not fed the milk from his mother’s breast. Instead, he is nurtured by Themis on nectar and ambrosia, the ‘food of the gods’. Themis is the goddess of prophecy, wisdom and good counsel, the personification of justice and the interpreter of the gods' will.
“In psychological terms, the double parentage motif tells us that the urge to individuation has a twofold source: personal factors and also transpersonal ones. It stems from the care and loving attention that actual persons such as the parents give the individual, but it derives as well from the archetypal roots of its own being, from divine knowledge.” ~ Edward Edinger, The Eternal Drama
In the Eumenides (lines 1-9), Aeschylus explains how possession of the oracle - and thus the Temple of Delphi - was handed down from Gaia, its founder, through Themis and Phoebe to Apollo . The Oracle is synonymous with intuitive thoughts, premonition.
When Apollo is just four days old, he slays Python, the serpent that had chased his mother whilst she was pregnant. In other versions, Apollo is said to have killed Python at Delphi where the serpent had taken over providing oracles.
Carl Kerenyi notes that the serpent is also called Delphyne, "which is constructed from the root delph- 'belly, uterus.' Delphi was also considered to be the “womb of the earth” . In ancient Greek, the word “Delphys” means womb, and Delphi was recognised as the centre of the world. 
Apollo is best known as the god of prophecy and the sacred sanctuary at Delphi was dedicated in his honour. It was here that the famous oracle is said to have channelled Apollo’s divine knowledge and the will of his father.
Inscribed on his temple at Delphi were the precepts:
Keep women under rule (Keep emotions under control)
The temple at Delphi was shared by Apollo and his half-brother, Dionysus. The latter is said to stay in the temple during the winter whilst Apollo retreated to Hyperborean; a paradise of bliss that shares similarities to the Underworld of Hades.
Together with prophecy, Apollo is associated with more attributes than any other god. He is recognised as the god of archery, culture (music, dance and poetry), healing and diseases, law and order, herds and flocks, the founder of cities and protector of the young.
Later, he became known as the sun god and was also known as Phoebus meaning “bright” and “pure”. As the personification of the sun, Apollo illuminates the sky (conscious mind) and the earth (subconscious mind). However, in Greco-Roman artwork, Apollo is depicted as a young man, indicating that his conscious nature is not fully developed.
“The Sun, is metaphorically sensed as the ego-friendly world of the spirit and is personified as the benevolent All-Father, disconnecting from the womb and taking a new attitude up to the world.” ~ Ena Stanley: Archetypes of Astrology
The myths of Apollo typically recount the god's desire for mortals and nymphs, both men and women. However, despite his radiance, the sun god is curiously unlucky in love.
In one myth, Apollo is struck by the arrow of Eros after the sun god taunts him about his inferior skills in archery. The arrow causes Apollo to fall in love with the mountain nymph, Daphne whom Eros had poisoned with a love-repealing arrow.
The mortal Marpessa, the nymph Sinope and Cassandra of Troy all spurned the god’s advances. Hestia, the goddess of the Hearth also refused his hand in marriage.
That said, Apollo had many love affairs and he fathered multiple children, the most famous of which were his divine offspring; Asclepius the god of healing; Aristaeus, the god of beekeeping, the Samothracian Corybantes, dancing demons, and Scylla, the sea-nymph resulting from his affair with Hekate.
Many of Apollo’s other offspring were kings, princes and princesses . His fathering of royalty also lends to his epithet as the founder of cities.
Callimachus tells us, "Your mother surely, begat you as a helper, and since then you live in song.”  He is also known as a god with the power to purify polluted waters, dispel fear and deliver cities from epidemics. Here we see his association with healing.
Scholars believe Apollo could also bring destruction. It was the god of archery that struck Achilles with his arrow. He was also responsible for the demise of the satyr Marsyas and the death of Zeus’ armourers, the Cyclopes. His furious father sentenced Apollo to a year's servitude as a shepherd for King Admetus of Therae.
Admetus treated the god with great kindness. In appreciation, Apollo blessed the king's herds and flocks so that they bore twins. He was also the king’s lover and intervened on his behalf when he was in the hands of Death.
It was also Apollo that prompted Orestes to kill his mother Clytemnestra and her lover Aegisthus to avenge the death of his father, Agamemnon. When brought to trial, Apollo defended Orestes against charges of murder.
Apollo also tricks his sister Artemis into killing the hunter Orion. The sun god had become jealous of his sister’s affection for Orion. One day whilst Orion was swimming in the sea, Apollo challenged Artemis to shoot an arrow into the speck on the horizon. Not realising her target was the man she loved, Artemis took aim and killed Orion.
As the protector of herds, flocks and crops, Apollo was responsible for preventing disease and pests. In classical times, his primary religious function was to keep away evil. He was therefore called “apotropaios”, a reference to apotropaic magic that is said to protect people from harmful influences.
Apollo’s penchant for protective magic links him to healing qualities. He was given the epithet, Paean, meaning “the Healer” and his most famous son is Asclepius, the god of medicine.
Scholars note that Apollo’s connection with music is connected to his role as a Paean.
The gods Wikipedia page reads:
“About the 4th century BCE, the paean became merely a formula of adulation; its object was either to implore protection against disease and misfortune or to offer thanks after such protection had been rendered. It was in this way that Apollo had become recognized as the god of music.”
The symbolism related to Apollo points to the god representing self-awareness. The sun is a symbol of the light that shines in the ego-conscious mind.
In psychological terms, the sun represents an illuminating quality that is needed for an individual to learn something about themselves and transform weakness into strengths (regenerate).
For example, a limiting belief that prevents you from moving forward, or a negative attitude that ruins relationships can be dispelled by Apollonian energy if you choose to change your beliefs or attitude.
“The visible father of the world is the sun, the heavenly fire, for which reason father, God, sun, and fire (and libido) are mythologically synonymous. The well-known fact that in worshipping the sun’s strength we pay homage to the great generative force of Nature (brackets are mine).” ~ Carl Jung, Symbols of Transformation
Self-realisation is essential for self-development and expanding conscious awareness.
This idea is further expressed in the numbers attributed to the Greek god Apollo; four, seven and nine. Born on the 4th of March, this day is sacred to him. When he was born, seven singing swans are said to have circled the island of Delos. Leto was also in labour for nine days and nine nights with her son.
In number symbolism, the four is the point in a cycle when energy becomes manifest as physical reality. The seven is the point in which the light of understanding enables you to see your weaknesses and mistakes. Nine is the end of the cycle in whereby the energy you have transmuted during this period becomes part of your subconscious program.
Homer also describes Apollo as “the night” and casts him shooting a slivery bow. His arrows are described as gold. The silver bow is synonymous with the moon, the night with ignorance. Apollo’s bow and arrow are, therefore, symbolic of an Apollonian epiphany, in which you reach self-actualisation.
This idea is also reflected in the seven signing swans that circled the island of Delos during Leto’s labour. In number symbolism, the seventh stage of a cycle is where the light of understanding enables you to see your weaknesses, mistakes or aspects of your personality that were previously in the unconscious.
 Eumenides (lines 1-9), Aeschylus
 Carl Kerenyi, Apollo
 Fontenrose, J. E. The Delphic Oracle, its responses and operations, with a catalogue of responses, 1974, Berkeley: University of California Press.
 and  Callimachus, A Hymn to Apollo translated by A. W. Mair, London: William Heinemann; New York: G.P. Putnam's Sons. 1921