Moonlight consists of mostly sunlight (with little earthlight) reflected from the parts of the Moon's surface where the Sun's light strikes. History. The ancient Greek philosopher Anaxagoras was aware that "the sun provides the moon with its brightness". Zhang Heng's treatise "The Spiritual Constitution of the Universe" concludes that the light of the moon comes from the Sun. He writes that the Sun and Moon are "like fire and water" where the Sun "gives out light" and the Moon "reflects it". . Illumination.
https://en.wikipedia.org/wiki/Moonlight