Classical World Chess Championship

In 1993, World Champion Garry Kasparov and official challenger Nigel Short split from the International Chess Federation (FIDE) and created the Professional Chess Association (PCA) for the marketing and organization of the world championship match. In response, Kasparov and Short were stripped of their titles and removed from their rating lists, and an "official" match was held between former world champion Anatoly Karpov and candidates runner-up Jan Timman.

Kasparov and Short, both complaining of corruption and lack of professionalism within FIDE, held a title match under the auspices of the PCA. As a result, two world championship matches took place simultaneously in 1993, with Kasparov retaining his PCA title against Short, and Karpov regaining his FIDE title which he had previously lost to Kasparov in 1985.

For the next 13 years, the title for World Champion was split and, after the PCA folded in 1996, the "unofficial" championship matches came to be known as the Classical World Chess Championship.

1996-2000
The Professional Chess Association folded in 1996 after being unable to find a sponsor for its world championship match. As a result, Kasparov (who had successfully defended his title to Viswanathan Anand in 1995) was unable to organize a proper qualifying cycle for his title. A candidates match was held between Vladimir Kramnik and Alexei Shirov, the next two best players in the PCA rating list, and won by Shirov. However, being unable to come to an agreement, Kasparov instead pursued a rematch with Anand. However, after negotiations failed in 1999 and 2000, Kasparov successfully negotiated a match with with Kramnik, and the company Braingames was founded to organize and finance a Kasparov-Kramnik match in October 2000.

2000-2006
Kramnik won the 2000 match against Kasparov, becoming the 14th world chess champion. He gave the cycle the name "Classical" to express its continuity with the PCA title. In July 2002, a candidates tournament was won by Peter Leko to challenge Kramnik's title, but the world championship match faced delays in finding a sponsor for the match. Finally in September and October of 2004, Kramnik successfully defended his title against Leko.

After over a decade of a split world championship title, in 2006, it was agreed that a reunification match would be played between Kramnik, the Classical World Champion, and Veselin Topalov, the FIDE World Champion. The match was won by Kramnik, becoming the first undisputed world chess champion in 13 years.