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
Marathon later recognized by the race organizers as the women's winner for that year, as well as 1967 and 1968. The length of an Olympic marathon was not precisely fixed at first, but the marathon races in the first few Olympic Games were about , roughly the distance from Marathon to Athens by the longer, flatter route. The exact length depended on the route established for each venue. The International Olympic Committee agreed in 1907 that the distance for the 1908 London Olympic marathon would be about 25 miles or 40 kilometres. The organisers decided on a course of 26 miles