Given Essig's personality and political position, it is likely, but not clearly documented, that he deliberately combined his desire to promote his town with his desire to promote his business. Our best records indicate that in 1846 he declared the "creation" of the Leonberger as a legitimate breed of dog.

The town crest of Leonberg contains a lion rearing up on its hindquarters. Although it is not known for sure if the town name refers to a lion, there is a definite association through the crest. The Leonberger, as we know it today, is lion-like in appearance. However, Essig's early versions certainly weren't. According to Essig, he crossbred a black-and-white female Landseer with a long-haired Saint Bernard that he had acquired from the Saint Bernard monastery in Switzerland. The puppies were, of course, black and white. He reportedly then crossbred these dogs for four generations, outcrossing with a yellow-and-white Saint Bernard and later a white Pyrenean Mountain Dog that he had in his kennels. He was striving at this early stage for an all-white dog, because they were very fashionable at the time.

It was only many generations and outcrossings later that the golden color and black mask became typical. Early records indicate that in 1865, Essig showed a dog at the Octoberfest in Munich that was described as a fine dog, resembling a lion, yellow and brown, with black tips.It is important to note here that the Leonberger we know today could not have come from the matings that Essig initially described. As has been pointed out by Letellier and Luquet in France and Nijboer in Holland, the AY allele does not exist in the three breeds that were supposed to be the originating breeds. Also, from a genetic standpoint, the Leonberger head is morphologically much different from that of the Saint Bernard or Newfoundland.

It is highly likely that local farm and butcher dogs with relatively fixed genetic characteristics, but not identified as a breed, found their way into the developing breed lines. Very large dogs with appropriate coloration and with heads shaped similarly to the Leonberger, as we know it, were known in the region and are described in 17th- and 18th-century literature. Also, intriguing documentation suggests that dogs from Leonberg were used at the Hospice of Saint Bernard in 1830, well before the origination of the Leonberger, to breed with the only Saint Bernard to have survived an outbreak of distemper.

Whether Essig actually created a new breed by careful selection following genetically sound principles is rather doubtful. What we do know for certain is that Essig bred, acquired, and sold some very imposing, beautiful dogs. We also know that his marketing genius resulted in such widespread popularization of the breed that the Leonberger, as a breed, survived cries of outrage from breeders of Saint Bernards and Newfoundlands, from judges, and from the editors of dog magazines. Essig was free to travel and promote his animals, because his niece, Marie, who was known as the "soul" of the kennel actually trained and maintained the animals. At the same time that he was being attacked, Essig's ardent loyalists paid great sums for his dogs and defended him publicly. Essig's Leonbergers caught the attention of popular German artists who used the dogs as models and this also increased their popularity. Through Essig's marketing skill, his dogs found their way into the castles of royalty, such as the Empress Elizabeth of Austria, the Prince of Wales, Emperor Napoleon II, Garibaldi, the King of Belgium, Bismarck, King Umberto of Italy, and the Czar of Russia. They were exported as far away as the United States, England, Newfoundland, and Japan to the wealthy who desired large fashionable dogs.

Essig died in 1889 without ever having defined a standard for the breed or a defensible description of his breeding program. It is a tribute to the qualities of the Leonberger that in spite of these obvious deficiencies, and in the face of ever harsher critics, there were enough enthusiastic owners to form, beginning in 1891, the first Leonberger clubs. Four years later, the first significant club, the International Leonberger Club founded in 1895 in Stuutgart.

The Club President, Albert Kull, was an artist with an eye for detail. He wrote the first standard for the Leonberger. This standard formed the foundation for all subsequent standards. Kull's work did much to reestablish the credibility of the breed, and the Leonberger began to flourish with three more serious clubs being founded.

World War I almost rendered the breed extinct. If it were not for the determination and dedication of two men, Herr Stadelmann and Herr Otto Josenhans, the breed would surely have become a mere footnote in the history of German dogs. After the War, Stadelmann and Josenhans scoured Germany searching for Leonbergers. They found 25. Of these, only five were suitable for breeding. Because of inflation and food shortages, it was unlikely that individuals could have personally and individually supported breeding programs, so a group of seven people joined together in 1922 to form the Leonberger Hunde Club in Leonberg and a breeding cooperative known as the Leonberger Hundezucht Genossenschaft. Within four years, they had selectively bred 350 Leonbergers. The organized breeding program of the Genossenschaft brought about a revival of the breed, brought honor to the town, and provided foundation stock to establish several kennels. Most notably, these men established the official Breed Registry, which continues uninterrupted today.

Stadelmann's work progressed until the early 1930s, when the authoritarian control of the Third Reich began to influence the dog world. A Reich-governed club, the Fachschaft für Leonberger, was established in Sandhausen when the Reich assumed control of all breed registries. Surprisingly, breeding, although very reduced, continued throughout the war. Both dogs and accurate records survived the destruction. In 1945, 22 puppies were registered and in 1946, 17.

At the end of the war it again took a group of devoted enthusiasts to reestablish an organized breeding program. Two rival clubs were established in 1946 and 1947. The club founded by Albert Kienzle, Hans Weigelschmidt, and Otto Lehmann became in 1948 the present-day Deutsche Club für Leonberger Hunde. In the early '50s, the Breeding Committee Chairman, Werner Lutz, and the third president of the DCLH, Robert Beutelspacher, wrote the first modern-day standard and breeding regulations, which had a profound impact on the development of the Leonberger as we know it today. In 1975, the German Club brought all the Leonberger breed clubs from the major European nations together and founded the International Union of Leonberger Clubs. Now, clubs from 17 nations correspond frequently and meet annually on the last weekend in September in Leonberg to work cooperatively to protect the health and quality of Leonbergers and to insure homogeneity of the breed throughout the world. Today, the Union is led by the President of the Deutsche Club für Leonberger Hunde, Gerhard Zerle.