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
2012 Olympic Marathon Course as 42.195 km and specifically state that the course must not be less than this distance. The rules further state that in Olympic competition the standard distance may not be exceeded by more than 0.1%. In order for a marathon performance to be ratified as a world record by the IAAF, the course must also meet other criteria that rule-out "artificially fast times" produced on courses aided by downhill slope or tailwind: the distance between start and end points when measured in a straight line should not exceed 50% of the length of the course (21.092 km in the case