Marathon world record progression races were first held in 1896, but the distance was not standardized by the International Association of Athletics Federations (IAAF) until 1921. The actual distance for pre-1921 races frequently varied slightly from the present figure of 42.195 km (26 miles 385 yards). In qualifying races for the 1896 Summer Olympics, Greek runners Charilaos Vasilakos (3:18:00) and Ioannis Lavrentis (3:11:27) won the first two modern marathons. On April 10, 1896, Spiridon Louis of Greece won the first Olympic marathon in Athens, Greece in a time of 2:58:50; however, the distance for the event was reported to be only 40,000 meters. Three
IAAF World Half Marathon Championships IAAF World Road Running Championships. Aside from the name change, the significant difference was the distance of the race, changing from a half marathon to a 20 kilometres road race. The 20 km race featured only at the 2006 edition, and the half marathon distance returned for the 2007 World Road Running Championships. On 29 November 2007, the IAAF announced that the name of the competition would revert to its original title of the IAAF World Half Marathon Championships, beginning with the 2008 IAAF World Half Marathon Championships in Rio de Janeiro, Brazil on 12 October 2008. This competition should