The Adventures of Prince Achmen (1926)

Lotte Reiniger's 65-minute-long stop-motion shadow-puppet 1926 film The Adventures of Prince Achmen is based on The Arabian Nights. It is the oldest surviving feature-length animation. It features a silhouette animation technique Reiniger invented which involved manipulated cutouts made from cardboard and thin sheets of lead under a camera.

Here's a clip:



Via bookofjoe