The Spanish Mastiff or Mastín Español is a breed of mastiff from Spain, originally bred to be a guard dog and whose specialized purpose is to be a livestock guardian dog protecting flocks and/or herds from wolves and other predators.
Image credit: Canarian, CC BY-SA 3.0
Adapted from Wikipedia, CC BY-SA 4.0 — https://en.wikipedia.org/wiki/Spanish_Mastiff