The stadium held the opening and closing ceremonies of the 1896 Olympics. On 6 April (25 March according to the Julian calendar then in use in Greece), the games of the First Olympiad were officially opened; it was Easter Monday for both the Western and Eastern Christian Churches and the anniversary of Greece's independence. The stadium was filled with an estimated 80,000 spectators, including King George I of Greece, his wife Olga, and their sons. Most of the competing athletes were aligned on the infield, grouped by nation. After a speech by the president of the organizing committee, Crown Prince Constantine, his father officially opened the games. The stadium also served as the venue for Athletics, Gymnastics, Weightlifting and Wrestling.