Simplify the following text for a Grade 7 native English-speaking person.
Original: The American Staffordshire terrier is a medium-sized , short-coated dog breed whose early ancestors came from England . In the early part of the twentieth century , the breed gained social stature and was accepted by the American Kennel Club as the American Staffordshire Terrier .
Simplified: The American Staffordshire Terrier is a breed of dog .