Short answers, pulled from the story.
Hesiod's Theogony lists Eros as the fourth god to emerge from Chaos after Gaia and Tartarus. He appeared establishing love as a fundamental force of creation rather than a later addition to the divine order.
Parmenides declared Eros the very first god to exist before all other deities. His fragment 13 states that she devised Erōs before any other gods came into being.
By the third century BCE epic writers referred to him simply as Venus's son instead of a cosmic entity. Later accounts stripped away primordial grandeur to replace the creator figure with a mischievous youth who intervened in affairs of gods and mortals.
Thespiae hosted a fertility cult dedicated to him while Athens shared a popular cult where the fourth day of every month was sacred to him. Pausanias recorded these events in Description of Greece book 9 section 31.
Early Greek poetry and art depicted Eros as a young adult male embodying sexual power before satirical poets transformed him into a blindfolded child. A red-figure terracotta plate from 340, 320 BC shows Eros with his bow at the Walters Art Museum.