Georg Hackenschmidt (generally spelled "George" in English-speaking countries) was the first undisputed world heavyweight champion of professional wrestling. He started claiming the title around 1900/04 and won the tournaments various European cities such as Paris, Hamburg, St. Petersburg, Elberfield, and Berlin in 1901. In November of the same year, he
defeated Ahmed Madrali in Vienna to be recognized as world champion.
In 1905, the "Russian Lion" defeated American heavyweight champion Tom Jenkins in New York City to become the undisputed champion.
He held the title until he lost it to Frank Gotch in 1908. This bout and the rematch in 1911 were both said to be controversial because of the way Gotch prepared for and fought the matches. In the same year, Hackenschmidt retired due to continuous injuries. After retiring from wrestling, he became a pioneer of weightlifting and wrote several books on training.