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 along the Victoria Embankment with the regular London Marathon course, the Olympic event also started in The Mall whilst the London Marathon starts in Greenwich, and the event followed an otherwise different course. The logistical problems behind the design of the London Marathon course (35,000 runners of mixed ability) are very different from those behind the design of the London Olympic Marathon course (100 top-class runners) hence the difference in the routes. The course for the Paralympic Marathon also had four laps which were nearly identical to the 2012 Olympic Marathon course, but avoided certain cobbled areas notably Paternoster Square,