The roots of this breed are in Spain. Written information can be found as far as the 14th century. That time the king of Aragonia, Ramino I El Monjella had a few black and white dogs that were called Pyrenean Mastiffs.
Pyrenean Mastiff is a very old breed, that stem from molossoid type dogs which the Foinikians brought with them to Spain on their trade trips about 300 b.c. The white mountain dog breeds are thought as the closest relatives of the PM.
Pyrenean Mastiff was for centuries the guardian of Aragonian sheep herds against wolves and bears. As the Pyrenean Mastiff stood on guard, shepherd dogs herded the sheep. Both the ears and tails were cropped to avoid injuries in battles against predators. Now it is illegal to crop, so the dogs get to keep their long tails and their drop ears.
The history of the Pyrenean Mastiff can be compared to the history of Pyrenean Mountain Dog, as they were originally the same heterogeneous breed. They worked in the same areas in the same duties until year 1659, when the two breeds diverged. The French started to breed the Pyrenean Mountain Dog to be an aristocratic pet for the upper class. On the Spanish side of the border Pyrenean Mastiff was still seen as an important working dog, which was not bred for the exterior appearance as much the working features.
To own a Pyrenean Mastiff at the early 19th century was subject to license: One Pyrenean Mastiff for a herd of 200 sheep. Enemies that the dogs had to protect their herd against were the mountain wolves and bears. As the wolves were hunted to extinction and the dark ages of Spanish civil war burst, were the enormous wolf fighters nearly extinct too.
Daniel Lorensin, Pere Fontin, Jose Masipin and Rafael Malo Alcrudo were the people who started to collect the remaining dogs in the 1970s. Resuscitation of the breed was started with 70 individuals. All of them were definitely not the best type, but they all were crucial to maintain a sufficient level of genetic diversity.
Between the years 1973 and 1979 the main task of the Spanish breed association, Mastin del Pirineo de España, was to find and save the few excellent type dogs, who still worked in the Pyrenean Mountains. Next step for the association was to form a sane plan for breeding and spreading the Pyrenean Mastiff, primarily in Spain. At the beginning the population started growing in the original grounds in Aragonia and there after it slowly strengthened in other areas of Spain. After a few years the abroad countries started to show interest in Pyrenean Mastiff as well. The first new country was Sweden and not many months later Finland.
First individuals were brought to Finland in the year 1985.