The term "bulldog" was first used around 1568 and might have been applied to various ancestors of modern bulldog breeds.
It has been theorized that Bulldogs were bred in England as a cross between the mastiff and the pug, although their genetic
origin is debated. In the 1600s, bulldogs were used for bullbaiting (as well as bearbaiting), a gambling sport popular in the
17th century with wagers laid in which trained bulldogs leapt at a bull lashed to a post, latched onto its snout and attempted
to suffocate it. However, the bulldog's early role was not limited to sports. In mid-17th century New York, bulldogs were
used as part of a city-wide roundup effort led by governor Richard Nicolls. Because cornering and leading wild bulls was
dangerous, bulldogs were trained to seize a bull by its nose long enough for a rope to be secured around its neck. In time,
the original athletic bulldog was crossed with pug. The outcome was a shorter, wider dog with a brachycephalic skull. Though
today's bulldog looks tough, he cannot perform the job he was originally created for, as he cannot withstand the rigors of
running and being thrown from a bull, and cannot grip with such a short muzzle.
This information was taken from Wikipedia.