Answer
Mikhail Botvinnik was the World Chess Champion from 1948 to 1957, and again from 1958 to 1960. He regained his title after losing it in both cases by defeating Then-reigning champion in a rematch. In 1951, Botvinnik lost the title to David Bronstein, but defeated him in a rematch in 1954. In 1957, Botvinnik lost the title to Vasily Smyslov, but defeated him in a rematch in 1958.