Which boxer relinquished his world welterweight title after defeating Jake La Motta in 1951?

Question

Which boxer held the World Welterweight title from the end of 1946 to 1951, at which point he then won the World Middleweight title?

Answer 1

Sugar Ray Robinson
Sugar Ray Robinson was an American professional boxer who competed from 1940 to 1965. Robinson's performances in the welterweight and middleweight divisions prompted sportswriters to create "pound for pound" rankings, where they compared fighters regardless of weight.