The Sinking of the Lusitania (1918)
This is a rare twelve minute animated documentary and is presumably the oldest of its kind to surface. Winsor McCay is the cartoonist/animator behind the animation, as he made ten animated films between 1911 and 1921. The film is propaganda that represents the sinking of the Lusitania, since there were no photographs of the incident which occurred in 1915.
Source: TheVideoCellar