Q: Who Was The Greatest Wrestler Of All Time?

A:  Milo of Croton (according to  listverse)

"Most historians agree that Milo remains to this day the greatest wrestler and fighter (from any combat sport) the world has ever known. Milo of Croton became an Olympic champion several times during his nearly thirty-year career. His size and physique were intimidating, and his strength and technique perfect—and many people accordingly believed that he was  the son of Zeus."

Perseus tells us more:

"According to our ancient sources, Milo enjoyed showing off his unrivaled strength. For instance, he would clasp a pomegranate in his hand and have others try to take it away from him. Even though he was holding it so tightly that no one could remove it, he never damaged the fruit. Sometimes, he would stand on a greased iron disk and challenge others to push him off of it. Another of his favorite exhibitions was tying a cord around his forehead, holding his breath, and breaking the cord with his bulging forehead veins. Other times, the wrestler would stand with his right arm at his side, his elbow against him, and hold out his hand with thumb pointed upwards and fingers spread. No one could successfully bend even his little finger. "

A Princeton webpage tells us he is supposed to have been close to Pythagoras:

"Milo was said to be an associate of Pythagoras. One story tells of the wrestler saving the philosopher's life when a roof was about to collapse upon him, and another that Milo may have married the philosopher's daughter Myia."