Simplify the following text for a Grade 6 native English-speaking person.
Original: Later , it assumed the name of Staffordshire Bull Terrier in England . These dogs began to find their way into America as early as 1870 , where they became known as the Pit Dog and Pit Bull Terrier , then the American Bull Terrier , and still later as the Yankee Terrier .
Simplified: Its early ancestors are the bull and the terrier , it used to be called the Blue Paul Terrier .