Emperor Shirakawa (白河天皇) was the 72th imperial ruler of Japan and the first to ostensibly retire to a monastery, but in fact to continue to exert influence over his successor. This process would become known as cloistered rule.
... See Professor Edward Felten's freedom-to-tinker Web site for information and pointers.
An early example of a DRM system is the Content Scrambling System (CSS) ...