They perhaps descended from the ancient Alaunt and Pugnaces Britanniae, with a significant input from the Alpine  Mastiff in the 19th century. Distinguished by its enormous size, massive head, short coat in a limited range of colours, and always displaying a black mask, the Mastiff is noted for its gentle and loving nature. The lineage of modern dogs can be traced back to the early 19th century, but the modern type was stabilised in the 1880s and refined since. Pied Mastiffs occur rarely. Other non-standard colours include black, blue brindle, and chocolate (brown) mask. Some Mastiffs have a heavy shading caused by dark hairs throughout the coat or primarily on the back and shoulders. This is not generally considered a fault.