New hint: The breed was developed in a small country in Eastern Europe. I would name the country but then that would make it too easy to figure out. The breed was developed to be a guardian although it quickly became a gladiator in the ring, easily defeating the typical "champion" breeds including the APBT and EBT.
This breed is typically more of a property and personal guardian rather than a livestock guardian The final standard for this breed was written in 1991 as it is a re-creation of a much older mastiff that unfortunately died out during the early 20'th century.
Hehe at first glance it makes me think of a chi/pap mix LOL Then it dawned on me...BUT I had to do a bit of research to double-check if I was right (which I was) so I won't guess