The Pyrenean Mastiff or Mastín del Pirineo is a Spanish breed of large livestock guardian dog from the autonomous community of Aragón in north-eastern Spain. It was traditionally used to protect flocks during the annual transhumance to high summer pasture in the Pyrenees. It is a distinct and separate breed from the Spanish Mastiff or Mastin Español and from both the Pyrenean Mountain Dog and the Pyrenean Shepherd.
Image credit: TBjornstad 07:59, 6 October 2006 (UTC), CC BY-SA 3.0
Adapted from Wikipedia, CC BY-SA 4.0 — https://en.wikipedia.org/wiki/Pyrenean_Mastiff