Papp tangled with Hungary's Communist authorities as well as opponents in the ring in a career which made him the first boxer to win three Olympic gold medals.
The fluid, hard-hitting southpaw, known for his devastating left hook, totted up an astonishing 301 amateur wins against just 12 losses, with 55 of his victories ending in first-round knock-outs.
His Olympic career was equally as fearsome: in 13 bouts spread across London 1948, Helsinki 1952 and Melbourne 1956, Papp lost only one round - in the 1956 final, which he won 2-1 against America's Jose Torres.
Budapest-born Papp turned professional at 31 in 1957 but had to train in Vienna to become the first professional boxer from the Soviet bloc.
In 1965, he was denied a shot at reigning middleweight world champion Joey Giardello in the United States when the Hungarian Communist authorities revoked his passport, concerned about the sensitivities of a boxer from the Soviet bloc fighting for money in the focal point of the capitalist world.
"This is my one big regret in life," Papp said later. He retired undefeated as a professional and as European middleweight champion and was later awarded an honorary world title by the World Boxing Council, who also named him the best amateur and professional fighter of all time.