FIDE

FIDE (Fédération Internationale des Échecs) is the world chess organisation. All national federations are members. It decides matters like World Championships and changes in rules of the game.
FIDE was founded on 20 July 1924 in Paris, France. However, it had little influence until the end of World War II. The reigning world champion at that time, Alexander Alekhine, did not want to have anything to do with it. He regarded the world title as his personal property. This only changed when he died with the title, in 1946 (no other champion has ever died while holding the title). It was obvious that some method was needed to find a new champion. FIDE stepped in and, with Russian backing, put forward a solution. The strong Soviet Chess Federation only joined FIDE in 1946. It had a great influence, with resources and many young strong players.
After WW II.
In 1948 a tournament was organized to determine which of the world top players was entitled to call himself World Champion. The death of Alekhine had left a vacuum. Two previous champions, Emanuel Lasker and José Raúl Capablanca had died in the late 1930s. It was clear that a new champion would come from the younger players.
The six players chosen by FIDE were:
In the end, Reuben Fine dropped out, and the other five contested the event. Mikhail Botvinnik won the tournament and became the new world champion.
In 1950 the FIDE awarded its first IM ("International Master") and GM ("International Grandmaster") titles. However it was not until 1957 that FIDE formulated clear criteria to award these titles. In 1970 a new ranking system, the Elo-rating, was introduced.
Later years.
With the collapse of the Soviet Union FIDE lost a powerful partner. This resulted in a long period of trouble. In 1993 worldchampion Gary Kasparov and his challenger Nigel Short left FIDE. They founded their own organisation for professional top players, the PCA ("Professional Chess Association"). So now there were two worldchampions: one from FIDE and one from the PCA. 
It was not until 2006 that the dust settled down and a re-unification match between Vladimir Kramnik and Veselin Topalov took place. In 1999 FIDE was recognised by the International Olympic Committee. In 2001 FIDE played by anti-doping rules, trying to make chess for like a candidate for the Olympic Games.