In the ancient Olympic Games all the athletes were naked.The athletes wore a loincloth. Orsipus was a runner who won in the 15th Olympic Games of 720 BC. He took of his loincloth and became the first nude athlete. 

Kallipatira wanted to watch her son who was competing in the Games. When  he won , everyone saw she was a woman as she tried to hug him. That 's why there was a new rule: All  gymnasts must be naked also and not only athletes.