Already during the 16th century, Leonardo da Vinci had correctly gathered enough information and drawings to explain the nature of earthshine. In Da Vinci’s Codex Leicester, published in the early 16th century, he states his belief that the Moon possessed an atmosphere and oceans, and that it was a fine reflector of light because it was covered with so much water. He also speculated about how storms on Earth could cause the earthshine to become brighter or dimmer, which is indeed observable with modern instrumentation.
Leonardo Da Vinci is primarily associated with his artistic creations and his oddly inspired mechanical contraptions. However many people are unaware of his astronomical endeavors, more importantly his discovery of earthshine.