Photos: Michael Phelps at his earliest Olympics, and today

The Rio Olympics have been another display of Michael Phelps and the swimming team’s dominance. He’s pocketed three gold medals with more events left to complete. It is also his farewell to Olympic competition. At 31 years old, he is not expected to swim in Tokyo in 2020.

Through his five Olympic appearances he’s progressed from one of the youngest American Olympians ever during his debut at 15 in Sydney, to the most decorated in history with 25 medals, 21 of those gold, as of Aug. 11.

Take a look back at some of his earliest Olympic and other international competitions and contrast them with his performance today.