The stadium was constructed in the 5th century b.C., as it is evidenced by a walled up inscription. It seems that at the beginning there were no seats and the spectators would stand, sit on the ground, or possibly on wooden seats. During the 2nd century b.C. the famous benefactor of Athens, Herode Atticus had financed the construction of stone seats which were made of the local limestone of Parnassos. It is in the same period that was also constructed the large entrance with the triumphal arch, a unique feature for the ancient stadiums of Greece.
The northern part of the stadium was cut in the rock of mountain slope, whereas for the southern side landfill with a supporting wall was used. The entrance faces the East and has a large triple arch supported by four pillars; it is from here that both the judges and the athletes entered the stadium; those latter were vividly applauded by the audience. The length of the track is equal to one Roman stadion, that is to say it is 177,55 meters long and some 25 meters wide. Both the starting (“aphesis”) and the finishing point are found at the ends of the field and have slabs with cavities for the athletes’ feet. The stadium is hairpin-shaped, with two parallel blocks of seats which converge to a semicircle at the western end (the so-called “sphendone”). Special seats were provided for the judges. The stadium had a capacity of some 5.000 people; staircases constructed between the seats were previewed for better access.
So far the stadium has been partially restored, but the supporting wall still remains collapsed with parts of it scattered around.