Wladimir Klitschko is a fighter.
Professional boxing , or prizefighting , emerged in the early twentieth century as boxing gradually attained legitimacy and became a regulated , sanctioned sport . Professional boxing bouts are fought for a purse which is divided between the boxers as determined by contract . Wladimir Klitschko . After turning professional later that year , he defeated Chris Byrd in 2000 to win the WBO heavyweight title .