Charles Henry "Jack" Blackburn was an American boxer and boxing trainer. Fighting in the first half of his career as a lightweight and later a welterweight, he was known for an exceptional defense and fought many men above his weight class, including six bouts with the great Sam Langford. He fought Joe Gans three times in no-decision bouts, defeating him once according to newspaper accounts and made good showings against Harry Lewis, Philadelphia Jack O'Brien, and Harry Greb. He found most of his fame training 1937 World Heavyweight Champion Joe Louis, but also had a significant role in training 1926 Lightweight Champion Sammy Mandell. He helped to train World Bantamweight Champion Bud Taylor and World Light-Heavyweight Champion John Henry Lewis as well.

Samuel Edgar Langford was a Black Canadian boxing standout of the early part of the 20th century. Called the "Greatest Fighter Nobody Knows", by ESPN, Langford is considered by many boxing historians to be one of the greatest fighters of all time. Originally from Weymouth Falls, a small community in Nova Scotia, he was known as "the Boston Bonecrusher", "the Boston Terror", and his most famous nickname, "the Boston Tar Baby". Langford stood 5 ft 6+1⁄2 in (1.69 m) and weighed 185 lb (84 kg) in his prime. He fought from lightweight to heavyweight and defeated many world champions and legends of the time in each weight class. Considered a devastating puncher even at heavyweight, Langford was rated No. 2 by The Ring on their list of "100 greatest punchers of all time". One boxing historian described Langford as "experienced as a heavyweight James Toney with the punching power of Mike Tyson".