Selene was the earliest of the Greek moon goddesses, predating both Artemis and her Roman counterpart Diana.

from “Praise to the Moon” by Elen Hawke:

She is the sister of Helios, the sun god, and like him travels the sky in a horse-drawn chariot, though hers is silver and the journey is at night. Selene is young and beautiful with a white face . . . and has an expanded silver almost-half-moon crescent on her brow . . . Selene had many lovers, but her true love was Endymion, a shepherd whom she discovered in a cave and whom she seduced. Together Selene and Endymion had many daughters, Eventually Selene, knowing that Endymion was mortal and that she would one day lose him to death, begged Zeus to allow Endymion to choose whether to become immortal and stay with her or to remain mortal. Endymion chose immortality [despite Zeus’s condition] that he must remain asleep in his cave, where he was visited nightly by Selene.