Reference to Dark ("Drow") Elves Dating Back to 1884

"The three 'D Series' modules...owe little, if anything, to fiction. Drow are mentioned in Keightley’s THE FAIRY MYTHOLOGY, as I recall (it might have been THE SECRET COMMONWEALTH—neither book is before me, and it is not all that important anyway), and as Dark Elves of evil nature, they served as an ideal basis for the creation of a unique new mythos designed especially for AD&D. The roles the various drow are designed to play in the series are commensurate with those of prospective player characters. In fact, the race could be used for player characters, providing that appropriate penalties were levied when a drow or half-drow was in the daylight world."
-Gary Gygax, "Books Are Books, and Games Are Games, and Never the Twain...", Dragon #31

Below, is page 64 from the 1884 edition of Thomas Keightley's
The Fairy Mythology: Illustrative of the Romance and Superstition of Various Countries.