The undisputed heavyweight champion is, of course, a boxer who is recognised as world champion, in the heavyweight division, by each of the sanctioning bodies in professional boxing. Prior to the foundation of the New York State Athletic Commission (NYSAC) in 1920, and the National Boxing Association (NBA) in 1921, the world heavyweight championship was a lineal championship, which could only be won by defeating the existing title holder.
In the early Twenties, the lineal heavyweight champion was William Harrison ‘Jack’ Dempsey, otherwise known as ‘The Manassa Mauler’, and he became inaugural NBA champion on July 2, 1921 and inaugural NYSAC champion on July 24, 1922. Of course, this was long before the foundation of the World Boxing Council (WBC) in 1963, the International Boxing Federation (IBF) in 1983 and the World Boxing Organisation (1988) but, having held the NBA and NYSAC titles simultaneously between July 24, 1922 and September 23, 1926, Jack Dempsey was effectively the first undisputed heavyweight champion in history.
His reign came to an end at the hands of the hitherto unheralded Gene Tunney, who won the NBA title, by unanimous decision, at Sesquicentennial Stadium, Philadelphia. Tunney also won the rematch – later christened ‘The Long Count Fight’ – at Soldiers Field, Chicago, a year later in similar fashion.