Undisputed champion he was still described as "undisputed champion" by some reports. After Joe Calzaghe's super middleweight victory over Mikkel Kessler in November 2007, he was frequently described as "undisputed champion". Others disputed this, because although he held the WBA, WBC, and WBO belts, he vacated his IBF title in November 2006 rather than face a mandatory challenger, and immediately vacated other titles as well. The unified champion is defined as a boxer that holds at least two world championships of major sanctioning bodies (WBA, WBC, WBO or IBF) in their respective division. Around 2004, the World Boxing Association recognized three different
Weight class (boxing) different class if there is space in the tournament. At major events such as boxing at the Olympics, there is a limit of one boxer per country per weight class. A boxer may fight different bouts at different weight classes. The trend for professionals is to move up to a higher class as they age. Winning titles at multiple weight classes to become a "multiple champion" is considered a major achievement. In amateur boxing, bouts are much shorter and much more frequent, and boxers fight at their "natural" weight. One boxer is said to be better "pound for pound" than