Klitschko brothers 5 months & 13 days. Vitali retained the WBC Heavyweight Championship until 15 December 2013, relinquishing his belt in pursuit of his political aspirations in his native Ukraine. The Klitschko brothers jointly run the professional boxing promotion companies ""K2 Promotions"" and ""K2 East Promotions"", as well as the ""Klitschko Brothers Fund"", a charity organization. They appear together on German TV shows and commercials, have a website shared between them, and support each other's training and fights. After Vitali's retirement, Wladimir continued to reign as champion & successfully defend all remaining title belts except for the WBC belt. He eventually lost
Chris Byrd vs. Wladimir Klitschko the vacant belt. Confirmed bouts: Chris Byrd vs. Wladimir Klitschko Chris Byrd vs. Wladimir Klitschko, billed as Die Rache des Bruders (German for "Revenge Of The Brother"), was a professional boxing match contested on 14 October 2000 for the WBO Heavyweight Championship. After his shock victory over the undefeated Vitali Klitschko, following Vitali suffering a torn rotator cuff, Chris Byrd agreed to face his number one contender, and Vitali's younger brother Wladimir. Wladimir Klitschko had won ten fights in a row following his first pro loss at the hands of journeyman Ross Puritty in December 1998. Klitschko knocked Byrd down