Swimming was part of the first modern 1896 Summer Olympics games in Athens. In 1900 backstroke was included as an Olympic Event. In 1902 the trudgen was improved by Richard Cavill, using the flutter kick. In 1908, the world swimming association Federation Internationale de Natation was formed. Butterfly stroke was first a variant of Breaststroke, until it was accepted as a separate style in 1952.
From Wikipedia