In 1993, Garry Kasparov and Nigel Short broke ties with FIDE to organize their own match for the title and formed a competing Professional Chess Association (PCA). From then until 2006, there were two simultaneous World Championships and respective World Champions: the PCA or "classical" champions extending the Steinitzian tradition in which the current champion plays a challenger in a series of games, and the other following FIDE's new format of many players competing in a large knockout tournament to determine the champion. Kasparov lost his PCA title in 2000 to Vladimir Kramnik of Russia. Due to the complicated state of world chess politics and difficulties obtaining commercial sponsorships, Kasparov was never able to challenge for the title again. Despite this, he continued to dominate in top level tournaments and remained the world's highest rated player until his retirement from competitive chess in 2005.