According to the mystery religion of Orphism, in the beginning there existed Chaos, Night, and Darkness (Erebos). Night lays an egg, from which Eros ("sexual passion") hatches. Eros is the father (sometimes also the mother) of several generations of gods, leading up to the current order.

The myth of the world egg is common in the Orient, but rare in the west. Orpheus and Orphism are closely associated with those northern neighbors of the Greeks known as Thracians, and this latter group apparently played a role in introducing the myth to the Greeks. It probably was not widespread outside of Orphic circles. With its several generations of gods, it is a modification of the more widespread Kingship in Heaven tradition found in Hesiod. Its limited circulation might also explain why tthe comic playwright Aristophanes feels free to poke fun at the myth in his play The Birds (birds . . . eggs . . . get it?)