Before he converted to Islam and changed his name, Muhammad Ali was known as Cassius Clay. This video is of young Clay as an amateur. We’re not sure how old he is everywhere, but in the Olympics clip, Ali is just 18.
As an older boxer, he learned to rely more on heart and tactics, but as a younger fighter, Ali was lithe, supremely quick and his unorthodox style made him a very difficult opponent.
He had worked a lot of it out here already. You can see the shuffle, the unconventional way he held his fists (you can do that when you’re unbelievably quick).