[2] For much of his earlier career he fought just above the middleweight range, around 165-75, making him smaller than most of the heavyweights he met, he became an American citizen later in life.

These rules also outlawed head butting, holding the ropes, strangling, using resin, stones or hard objects in the hands, and biting.

[3] Fighting at a lighter weight on 2 June 1864 Allen lost in a battle for the welterweight championship of England to Bob Smith in a 50-round match at Widbury Isle.

[2] After several fights were stopped by Police, Allen and Joe Goss finally met on 5 March 1867 for the Middleweight championship of England in Gloucestershire.

[5] Allen lost to what many consider his most skilled opponent, Mike McCoole in an early career battle on 15 July 1869 at Foster's Island near St. Louis, for the heavyweight championship of America in a ninth round foul.

[7] In a title bout for the Heavyweight Championship of America on 17 August 1869, Allen drew with Charley Gallagher at "Foster's Island" near St. Louis, Missouri in eleven rounds.

Both boxers were injured, however, and both scored a number of blows, though the St. Louis Globe wrote that the match appeared decisively in Allen's favor, particularly after the seventh round.

The Globe also noted that Gallagher's seconds had thrown up the sponge to indicate a knockout loss by their boxer, but that the referee chose to rule the fight a draw nonetheless.

[8][2] On 10 May 1870, Allen was dealt a brutal ten round loss from well known middleweight boxer Jem Mace at Kennerville, Louisiana, before a substantial crowd of 2000, in a title bout for the heavyweight championships of both England and America.

Both men attempted to put the other in a headlock unsuccessfully, a strategy permissible by the lax London Prize Rules that governed the fight.

[9] On the day before the championship fight against Allen and Mike McCoole near St. Louis, both boxers were arrested and required to post a bond of $1,000 to keep the peace.

[10] Nonetheless, the fight took place the following day on 23 September 1873 with a seventh round win by Allen at Chouteau Island in Madison County, Illinois.

The taller McCoole, who many historians considered the more awkward boxer, took the fiercer punishment in the first three rounds, with Allen opening a cut on his right eye, which he continued to pound.

[2][11][7] Perhaps due partly to the number of spectators, and the high stakes involved, Allen was arrested two months later on the evening of 23 November for participating in the fight on a requisition from the Governor of Illinois.

[13] On 7 September 1876, Allen lost the Heavyweight championship of America to Joe Goss in 34 rounds in Boone County, Kentucky, taking one hour and fourteen minutes.

The fourth was fought viciously on both sides with blood streaming from Allen's nose, but equal damage being done to Davis, who went down after four minutes of fighting, ending the round.

[20] In his last professional fight, Allen again fought for the Heavyweight championship of England and a 400-pound purse against Jem Stewart on 22 April 1879 in London.

When he returned to the United States, his lawyer successfully argued for his release from the bond posted as a result of his arrest after his fight in Kentucky.