When did Ernst Lubitsch begin directing feature-length comedies?

Ernst Lubitsch began directing feature-length comedies by 1915. Prior to this transition, he had established himself as a popular comic actor in Germany, where he also wrote and directed a series of one-reel silent film comedies featuring the character Meyer. Following his move into feature-length work, he eventually left the company of stage director Max Reinhardt to dedicate himself fully to his directing career.1