Philadelphia Jack O'Brien

Joseph Francis Hagan (better known as Philadelphia Jack O'Brien) born James Francis Hagan or Hagen, and also identified in some sources as Joseph Francis Hagan, (January 17, 1878 – November 12, 1942) was an American professional boxer who held the world light heavyweight title in 1905 after defeating Bob Fitzsimmons. Active from the 1890s to the early 1910s, he competed across the middleweight, light heavyweight, and heavyweight divisions, and fought leading boxers of his era including Bob Fitzsimmons, Tommy Burns, Stanley Ketchel, Jack Johnson, and Sam Langford.