Development of the World Chess Championship became the first unified and undisputed World Chess Champion since Kasparov split from FIDE to form the PCA in 1993. Kramnik played to defend his title at the World Chess Championship 2007 in Mexico. This was an 8-player double round robin tournament, the same format as was used for the FIDE World Chess Championship 2005. This tournament was won by Viswanathan Anand. Because Anand's World Chess Champion title was won in a tournament rather than a match, a minority of commentators questioned the validity of his title. Kramnik also made ambiguous comments about the value of Anand's title, but did
World Chess Championship in later life, dated his reign from this 1866 match. In 1878, Johannes Zukertort won the Paris 1878 chess tournament (though Steinitz did not play), and later won the London 1883 chess tournament by a convincing 3 point margin, ahead of nearly every leading player in the world, including Steinitz. This tournament established Steinitz and Zukertort as the best two players in the world, and led to the inaugural World Championship match between these two, the World Chess Championship 1886. This match, won by Steinitz, though not held under the aegis of any official body, is generally recognized as the