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 2010 for the title of FIDE World Chess Champion would be an eight-player tournament. At the time there were two rival World Champions, 2005 FIDE World Champion Veselin Topalov, and "Classical" World Champion Vladimir Kramnik. The list of the eight players for the tournament included Topalov, but not Kramnik. To unify the two World Champion titles, FIDE later organised a match between Kramnik and Topalov (the World Chess Championship 2006). Kramnik was to take Topalov's place in the World Chess Championship 2007 if he won the match, which he did. Topalov was hence excluded from the 2007 World Chess Championship, a