It is believed to be originated in Molossus from the region of Minor Asia. Giving to their stoutness and courage these days were used by tribes whose subsistence depended on the shepherds, fulfilling a basic role in this type of community. With the appearance of the transhumance displacement, which led to the temporary displacement of great flocks, it was verified that they were exposed to several dangers during the great walks to the mountains in Summer and to the plains in Winter , the flocks were always accompanied by dogs of great stoutness, which gave origin to his spread from region to region. That's why this mighty dog of the plain from Alentejo, started to designated by Alentejo Mastiff. Since the end of the XIX century.