Regarding the more recent American history of the American Bulldog, I swiped this first portion for you off Wikipedia here, and so I've credited and backlinked to them. It is an excerpt from their previous American Bulldog page discussing the American Bulldog's well known history in the United States. I've added a few photos for you the original author didn't have...

"History in the United States" (American Bulldog history)

"The original bulldog was preserved by working class immigrants who brought their working dogs with them to the American South. Small farmers and ranchers used this all-around working dog for many tasks including farm guardians, stock dogs and catch dog. These dogs were not an actual breed as considered by today's standards but were a generic bulldog type. There were no recorded pedigrees or records and breeding decisions were dependent on the best working farm dogs despite breed or background. Several separate strains of the "bulldog" type dogs were kept by ranchers as utilitarian working dogs."

"By the end of World War II, however, these bulldog type strains were becoming extinct. Mr. John D. Johnson (pictured left), a returning war veteran, decided to resurrect this breed. He found many of the best specimens of these working type dogs and started recording pedigrees and family trees. His aim was to produce a large farm guardian-type bulldog, reminiscent of the bulldogs of old. Later Alan Scott and several other breeders joined Johnson's efforts to resurrect and recreate the old time bulldogs. Johnson and Scott began to carefully breed American bulldogs, keeping careful records and always with an eye for maintaining the breed's health and working abilities. Initially Johnson and Scott had a similar vision and even traded dogs with each other. However in time there was a split between their visions and resulted in the two distinct types of American Bulldog. Alan Scott preferred a smaller more athletic dog with a longer muzzle that could be used for cattle catching as well as wild boar hunting. John Johnson preferred a larger more massive dog with a shorter muzzle that was more of a guardian type dog. Over time the two founding breeders as well as important breeders crossed in other breeds to help meet their goal of the ideal working bulldog. Originally the breed was called the American Pit Bulldog and in the 1970s registered with the National Kennel Club (NKC) as such. Later the name was changed to American Bulldog to avoid confusion with the American Pit Bull Terrier. The American bulldog was recognized by the United Kennel Club on January 1, 1999. Currently the breed is recognized by the NKC, UKC and the American Bulldog Association (ABA)."

"Perhaps the most important role of the bulldog and the reason for its survival, and in fact why it thrived through out the South, was because of the presence of feral pigs, introduced to the New World and without predators. The bulldogs were the settlers' only means of sufficiently dealing with the vermin. By World War II, the breed was near extinction until John D. Johnson and his father scoured the backroads of the South looking for the best specimens to revive the breed. During this time a young Alan Scott grew an interest in Mr. Johnson's dogs and began to work with him on the revitalization process. At some point, Alan Scott began infusing non-Johnson catch bulldogs from working southern farms with John D. Johnson's line creating the now Standard American Bulldog. At another point, Mr. Johnson began crossing his line with an atavistic English bulldog from the North that had maintained its genetic athletic vigor. This created a falling out between Johnson and Scott causing them to go their separate ways and breed the two significantly different versions of the American bulldog. Also, in the year 2010, the breed of American Bulldogs was awarded the best breed of the decade." (from Wikipedia)

No doubt there are those who would argue or add to that history. Dog breeding is like that; brings out the cultural anthropologist in everyone - me too, but I don't think it matters that much and further, I think we make a mistake when we focus on the American Bulldog's American history, rather than the identity and histories of his progenitors. What interests me most is the American Bulldog's earlier, pre-American history, not only of the dog we now call the American Bulldog in his three primary types and multiple bloodlines, but also his cousins - maybe even brothers from long before...

Only two species have overcome and/or eaten every land animal on earth: humans and dogs. It seems more than coincidental that dog and man are also friends unlike any two species. Dogs and humans are found paired together in the art of most every ancient culture. Further, ancient art often shows us the same few dogs paired with man.

To the left, ancient Europeans refined large, white and dark colored breeds for the purpose of hunting. Pictured, one version of the now extinct Alaunt, descendant of Asiatic Masiffs bred to German Mastiffs and Bullenbeissers.

"The Romans made use of steppe nomads in their cavalry. Marcus Aurelius sent 5,500 Alans to Britian, where they guarded Hadrian's Wall. Their fierce Alaunt dogs went with them."

                     The Mastiffs, The Big Game Hunters
Their History, Development and Future
David Hancock, Charwynne Dog Features, 2002

Notice left that some of the dogs are significantly larger than the human handlers working with them. With the exception of the two dogs center and the Shepherd-like dog upper right, the other four dogs all clearly have the same brachycephalic head and heavy body type, just different colors. You could easily correlate the phenotype of these dogs to that of some modern breeds, yet this art is ancient, pre-dating the existance of dogs organized into "breeds." Modern breeders might ask themselves, are we breeding better or worse than the breeders who bred these dogs?

In the lower left corner, a progenitor of the American Bulldog, long before arriving in the New World and roughly the size of a man.

Again looking at the early European dogs to the left we see the very same dogs in our American Bulldog breed today. Note the large, round heads, two white dogs (one splotched with color; i.e., pie'd) and a darker dog between them with a spot on his back. These dogs could easily be litter-mates with each other and even a few rare American Bulldogs bred today.

These are clearly giant Bullmastiff type dogs shown in Europe hunting well over 1,000 years ago. Notice the colors: A pure white dog, a pure brown or red dog and a dog lighter in color with spots, all of the same size and type. Breed an American Bulldog to a Mastiff and you'll likely see these same three dogs in the litter.

Here a dog almost an exact replica of the Performance Line or Scott Type American Bulldog in a German painting of 1510. The white dog shown in the forefront - for all practical purposes lives in my back yard today, here depicted as the canine pride of royalty, the centerpiece of the painting - and beside him, a rightfully jealous hound.

The white dog's master with the long spear is a hunter; notice the horn at his hip, the twine and loops on his arm and waist. In ancient times wolves, bears, lions, and the centuries famous and feared wild boar were hunted with such dogs. This is not a hunting party, however, not with the ladies in their finery. This is a garden party, the hunter and his dogs present to protect the nobles from wild beasts. Nothing can screw up a garden party faster than a wild boar!

Take note also of the wide, metal "cut-collar," on the dog discussed. It is in fact similar to those used today on hog-dogs, protecting their throats from razor sharp tusks. It is the collar of a dog bred to go into battle, fearlessly confronting man and wild beast alike upon command. Some will say this dog is an early Greyhound, to which I reply, study your dog lore Sparky. At this point in history, Greyhounds, Mastiffs, Great Danes - all were the same stock.

And centuries later in the New World, the same dogs with the same purpose remained...

"In his History of Virginia, first published in 1705, Robert Beverly ...says that the hunters always took their "great dogs," their mastiffs and greyhounds, with them on these excursions to guard against wolves, bears, panthers, and wildcats."

A Dog's History of America
How Our Best Friend Explored, Conquered, and Settled a Continent
Mark Derr, North Point Press, 2004

Looking closely we see three distinct dog types featured in the painting: A large Bulldog or Mastiff type breed in the middle showing a large round head, prominant nasal stop, white underbelly, patches and heavy white on legs and face. He's about the size (relative to the men) of today's larger Bullmastiffs. Another large dog just below him, showing what seems to be longer black and tan fur and longer head, very much resembles the Irish Wolfhound from whence comes the Great Dane or German Mastiff. Last there are three pure white dogs - two of them very large, but all clearly the same typology, with large, elongated heads. Two of them are as large as men. These are the ancient Alaunt.

Of the the four dogs interested in the wild boar, all are clearly giant breed dogs, three being larger than the size of today's Mastiffs, but note the absence of fat and hanging skin. Each of the three distinct breeds shown are unquestionably bred to be very large running dogs used for hunting and as already mentioned, protection.

White coloring of the ancient Alaunt allowed it to be seen at night by his master and discerned from prey and livestock. Darker colored dogs on the other hand, provide stealth. Each have their purpose, but both were bred for speed, power, a hunting dog's olfactory and prey drive.

Copies of this painting by J. F. de Troy hangs in hunting clubs across Great Britain, rightfully demonstrating the long and unbroken history of England's famously capable Fox Hounds. However, look at the group of dogs I've circled. Notice the still very large size, but the slightly shorter legs and shorter, larger heads. There is no question but that these are a type of white Bullmastiff - what we call an American Bulldog today.