The Origin of Gandalf

"Before setting off on the return journey to England, Tolkien bought some picture postcards. Among them was a reproduction of a painting by a German artist, J. Madelener. It is called Der Berggeist, the mountain spirit, and it shows an old man sitting on a rock under a pine tree. He has a white beard and wears a wide-brimmed round hat and a long cloak...Tolkien preserved this postcard carefully, and long afterwards he wrote on the paper cover in which he kept it: 'Origin of Gandalf'." - from Tolkien by Humphrey Carpenter