The only event recorded at the first thirteen games was the stade, a straight-line sprint of just over 192 metres. The diaulos (lit. “double pipe”), or two-stade race, is recorded as being introduced at the 14th Olympiad in 724 BC. It is thought that competitors ran in lanes marked out with lime or gypsum for the length of a stade then turned around separate posts (kampteres), before returning to the start line. Xenophanes wrote that “Victory by speed of foot is honored above all.”
A third foot race, the dolichos (“long race”), was introduced in the next Olympiad. Accounts of the race’s distance differ; it seems to have been from twenty to twenty-four laps of the track, around 7.5 km to 9 km, although it may have been lengths rather than laps and thus half as far.
The last running event added to the Olympic program was the hoplitodromos, or “hoplite race”, introduced in 520 BC and traditionally run as the last race of the games. Competitors ran either a single or double diaulos (approximately 400 or 800 metres) in full military armour. The hoplitodromos was based on a war tactic of soldiers running in full armor to surprise the enemy.
Source: Wikipedia
