Answer
Floyd Patterson competed in professional boxing until the age of 37. He made his professional debut in 1952 at the age of 18 and won the world heavyweight championship in 1956 at the age of 21. He lost the title to Ingemar Johansson in 1959 but regained it in 1960. He lost the title again to Johansson in 1961 and retired from boxing in 1972.