[TheMercenary]

The Parson Russell Terrier was recognized by the UK Kennel Club in 1990, followed by Australia and FCI countries, then American Kennel Club in 2001, as Parson Jack Russell Terrier and then in the USA as the Jack Russell Terrier, Because the name Parson Jack Russell was registered in the USA by a person who did not wish to relenquish their trade mark, the Kennel Clubs of the world had to "re-badge" the PJRT to PRT to accommodate this problem. So now the taller type of Russell is a Parson Russell (over 12") and the shorter version is a Jack Russell (10-12").

The Parson Russell Terrier is descended from early white-bodied foxing terriers used in the hunt field. At the end of the 19th Century, these dogs were drawn into the Kennel Club as "fox terriers," but their still-working antecedents were referred to as "Jack Russell" terriers throughout the 20th Century, in honor of the Rev. John "Jack" Russell, a noted fox hunter of the 19th Century "The Sporting Parson".

In time, Kennel Club Fox Terriers and working Jack Russell Terriers looked completely different, with fox terriers growing both larger in the chest and also having longer heads.

The name was changed to "Parson Russell" Terrier for the American Kennel Club because of a compromise with the Jack Russell Terrier Club of America. The rest of the world recognises Jack Russell and Parson Russell as 2 separate breeds.

http://en.wikipedia.org/wiki/Parson_Russell_Terrier