M. Dretzen, a newspaper publisher in Paris, began to "Reconstitute" the breed, as he termed it in 1902. In 1907, he and Count Henri de Bylandt searched the Pyrenees Mountains for suitable specimens of the breed. Here they met and gained the assistance of Eugene Byasson, the registrar of justice of peace of Argelès-Gazost. It is said they examined over 350 dogs, choosing only a few as faultlessly typical examples examples of the breed. It is reported that M. Dretzen purchased these and returned with them to his kennel, Zaïlea, in Bois-Colombes (a Paris suburb) . M. Dretzen is universally credited with saving the breed. Champion Porthos, bred by a M. Castro, is his most famous dog and achieved the above honor in 1911. Porthos is specified as sans orgine or "origins unknown", so he might have been one of the dogs imported from the Pyrenees, but this is strictly speculation. It is important to connect the generations wherever possible and in this connection M. Dretzen writes to Mrs. Mary Crane in a latter dated, January 23, 1936 (finished on February 11, 1936 due to illness) that "M. Cazaux-Moutou (who, when student in Paris, had followed my breeding from 1905 to 1909 or 1910), when returned to his country, Lourdes (Hautes-Pyrenees), began breeding, together with other fanciers."(3) This was the founding of the famous "de Soum" Kennels that seems to be the cradle of the genetic origins of the breed in North America.
At the same time M. Byasson was instrumental in forming the Argelès-Gazost Club and M. Sénac-Lagrange along with others from the region had formed the Pastoure Club at Cauterets. Under the leadership of M. Sénac-Lagrange in July, 1923 in Tarbes the Réunion des Amateurs de Chiens Pyrénéens was formed. In 1927 they published their standard from which all other standards active in the world today are derived. M. Cazaux-Moutou and Sénac-Lagrange collaborated closely until the demise of de Soum after World War II. M. Sénac-Lagrange remained very active in the breed, as well as several other breeds, until his death. M. Sénac-Lagrange advised Madame Giralt of Comté de Foix on her initial breed selection. So we can essentially connect the efforts of M. Dretzen forward to today's contemporary dogs in France and now all over the world.