Earliest known painting of the moon

According to a scientist in Seattle named Scott Montgomery, Jan van Eyck's painting of the moon replaces Leonardo da Vinci's sketch by 100 years. Van Eyck had a penchant for depicting the moon in his paintings, mostly due to his philosophical stance as a Realist. 

If you look closely to the right, you will see the moon with recognizable surfaces.  And although the texts will give credit to Leonardo da Vinci as the first to depict the moon naturalistically, Montgomery says that they should be corrected, as van Eyck painted the moon in four different works (the above being the most popular.) (source: http://news.bbc.co.uk/1/hi/sci/tech/399918.stm)

As a realist, van Eyck wanted to show his world as it really was, only completely saturated with a divine presence. Thus, we see in his works a perfect concentration to detail, and a pictorial quality that is full of symbolism, both hidden and available.