The Boston Terrier was bred in Boston, Massachusetts from an English Bulldog and White English Terrier. The breed was originally bred as a vicious fighting dog that weighed up to 44 pounds. The breed we know today originated from a dog known as "Hooper's Judge" who lived around 1870. Hooper's Judge was bred with a smaller female and their offspring were bred down even further to form the modern Boston Terrier breed. The breed was accepted to the AKC in 1893 and is still a popular breed to this day.
http://www.akc.org/breeds/boston_terrier/
http://en.wikipedia.org/wiki/Boston_Terrier
http://www.dogbreedinfo.com/bostonterrier.htm