Actually the original pitbull was pure bred….which means they were not mixed with any other breed of dog. The pure bred pits are from back in Roman times. When they moved across land some time later, that’s when they started breeding with other “high end” breeds, such as the mastiff and terriers.
The “pit” came from back during the plague and being the infestation of rats, they would put these bulldogs in a pit and see how many rats they could catch. That’s where pitbull came from.
Most people think that a pitbull is a variety of breeds, but not the original pitbull…the original was “pure”. I personally don’t care for the look of an original pitbull myself.