Since at least John L. Sullivan, in the late 19th century, there have been world champions in professional boxing.
Manny Pacquiao has won world championships in eight weight divisions, more than any other boxer in history.
[5] When a champion, for reasons beyond his control such as an illness or injury, is unable to defend his title within the normal mandatory time, the sanctioning bodies may order an interim title bout and award the winner an interim championship.
[6] According to WBA championship rules, when a champion also holds a title of one of the other three major sanctioning bodies in an equivalent weight division, that boxer is granted a special recognition of "Unified Champion", and is given more time between mandatory title defenses.
[7] The WBC established many of today's safety measures in boxing, such as the standing eight count,[8] a limit of 12 rounds instead of 15, and additional weight divisions.
[9] In April 1983, the organization established an international division that was known as the United States Boxing Association-International (USBA-I).
[9] The World Boxing Organization (WBO) was founded in San Juan, Puerto Rico (which is a self-governing commonwealth of the United States) in 1988.
When The Ring started awarding titles again in 2001, it did not calculate retrospective lineages to fill in the gap years, instead nominating a new champion.