The Boston Yorkie is the result of a cross between two pure breeds, the Boston Terrier and the Yorkshire Terrier.
The Yorkshire Terrier was developed in the 19th century, by mill workers in the Yorkshire area who brought with them different Scotch terriers that were interbred and mixed with other small dog breeds. The Yorkie was bred to catch rats around the mills, but not much detail is available on the breed crosses. Some believe there was a Maltese in the mix, seen the long, lustrous coat of the Yorkie.
The Boston Terrier, nicknamed the "American Gentleman", is a polite, neat, gentle dog ideal as a lap dog and good with kids and older people. It has been used in therapy work, and is more disposed towards playing and cuddling rather than the general terrier personality of adventurousness and challenge.