Brian Nielsen (born 1 April 1965) is a Danish former professional boxer and Olympic bronze medalist. He held the IBO heavyweight title from 1996 to 1999 successfully defending it five times, including against Larry Holmes and Phil Jackson, the second highest number of defenses behind Wladimir Klitschko's record of 18. At one point of time, he equaled Rocky Marciano's record of 49 successive wins with no losses. While he never held a world title from any of the main four sanctioning bodies (WBC, IBF, WBA, WBO), he did defeat several former world champions who had, including James Smith, Jeff Lampkin, Tony Tubbs, Carlos De León, Tim Witherspoon, Orlin Norris, and Uriah Grant. Wikipedia