In the beginning, before the gods, there was only Chaos, the yawning void. Then Gaia, the Earth, arose, and Tartarus, the deep pit beneath the world. And then came Eros, primordial powers, born without parentage from the void itself. Hesiod, writing his Theogony around 700 BCE, describes him as "the fairest among the gods, who loosens the limbs and weakens the mind of all gods and mortals alike." Eros was a fundamental force of the universe, the power of attraction that drew unlike things together and created the bonds of nature. Without him, the cosmos would have remained scattered elements, never forming the ordered world.

But the Greeks told many stories about Eros, and over time his image changed. By the lyric poets in the 7th and 6th centuries BCE, he had become the son of Aphrodite, the goddess who rose from the sea-foam at the shore of Cyprus. Sappho wrote that he was born of Aphrodite and Ouranos, the Sky, while others said his father was Ares, making Eros the brother of Deimos (Fear) and Phobos (Panic). He appeared as a beautiful youth with golden wings, armed with a bow and arrows. His golden arrows caused irresistible love, while his lead-tipped arrows produced cold indifference. He was capricious, shooting at targets without warning.

The most famous tale is his love for Psyche, a mortal princess whose beauty was so extraordinary her people began to worship her instead of Aphrodite. The goddess, enraged, commanded Eros to make Psyche fall in love with the most hideous creature. But when Eros saw Psyche sleeping, he pricked himself with his own arrow and fell in love with her instead. He carried her to a hidden palace where he visited her only in darkness, forbidding her to look upon his face. For a time they lived in bliss, but Psyche's jealous sisters convinced her that her invisible husband was a monstrous serpent. One night, she lit a lamp and looked upon him as he slept, and saw his beauty. A drop of hot oil fell and woke him. Betrayed, Eros fled, and Psyche was cast out.

Aphrodite set Psyche impossible tasks. She had to sort a mountain of mixed grains in a single night, completed by ants who helped. She had to fetch the golden wool of deadly sheep, and fill a flask with water from the river Styx, the underworld. Finally she descended to the underworld to bring back a box of Persephone's beauty. Persephone, queen of the dead and wife of Hades, king of the underworld, gave her the box but warned her not to open it. Overcome by curiosity, Psyche opened the box and fell into a deathlike sleep. Eros found her and woke her with a touch. He flew to Zeus, king of the gods, and begged him to make Psyche immortal. Zeus granted the request, and Eros and Psyche were married on Olympus. Their daughter was Hedone, goddess of pleasure.

Eros was worshipped across Greece, but most famously at Thespiae in Boeotia, where his earliest image was a simple unworked stone. The city celebrated the Erotidia, festivals with games. In Athens, an altar to Eros stood at the entrance of the Academy, where Plato and his students later gathered. Praxiteles sculpted him as a bow-armed youth of perfect beauty. Over centuries, artists depicted him younger and younger, until by the Hellenistic period he had become a plump winged infant, the putto who would become the Roman Cupid and cherub. Plato, in his Symposium, elevated Eros to a cosmic principle, the force that drives the soul toward beauty and truth.