At the World Championship Trials fo

At the World Championship Trials for the 2001 World Aquatics Championships, on March 30, Phelps broke the world record in the 200-meter butterfly to become, at 15 years and 9 months, the youngest man ever to set a swimming world record, breaking the record previously held by Ian Thorpe when he lowered the 400-meter freestyle world record at 16 years, 10 months.[18] At the World Championships in Fukuoka, Phelps broke his own world record in the 200-meter butterfly en route to becoming a world champion for the first time.[19]