There are seventeen weight divisions. To compete in a division, a boxer's weight must not exceed the upper limit. Manny Pacquiao has won world championships in eight weight divisions, more than any other boxer, and is the only one in boxing history to achieve it. The Klitschko brothers, Vitali and Wladimir, held all four major titles in the heavyweight division from 2011 to 2013; they were the first brothers to hold versions of the heavyweight championship at the same time. Joe Louis holds the record of being the longest reigning world champion in boxing.