The English Mastiff, referred to by most Kennel Clubs simply as the Mastiff, is a breed of large dog perhaps descended from the ancient Alaunt and Pugnaces Britanniae. Distinguishable by enormous size, massive head, and a limited range of colours, but always displaying a black mask, the Mastiff is noted for its gentle temperament. The lineage of modern dogs can be traced back to the early 19th century, and the modern type was stabilised in the 1880s.
Following a period of sharp decline, the Mastiff has increased its worldwide popularity. With a massive body, broad skull and head of generally square appearance, it is the largest dog breed in terms of mass. Though the Irish Wolfhound and Great Dane are taller, they are not nearly as robust. The body is large with great depth and breadth, especially between the forelegs, causing these to be set wide apart.
The colours of the Mastiff coat are differently described by various kennel clubs, but are essentially fawn or apricot, or those colours as a base for black brindle. A black mask should occur in all cases. The fawn is generally a light "silver" shade, but may range up to a golden yellow. The apricot may be a slightly reddish hue up to a deep, rich red. The brindle markings should ideally be heavy, even and clear stripes, but may actually be light, uneven, patchy, faint or muddled. 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. Brindle is dominant over solid colour. Apricot is dominant over fawn, though that dominance may be incomplete. Most of the colour faults are recessive, though black is so rare in the Mastiff that it cannot be certain if it is recessive, or a mutation that is dominant.
The greatest weight ever recorded for a dog, 343 pounds (156 kg), was that of an English Mastiff from England named Aicama Zorba of La Susa, although claims of larger dogs exist. According to the 1989 edition of the Guinness Book of Records, in March 1989, when he was 7 years old, Zorba stood 35 inches (89 cm) at the shoulder and was 8.25 feet (251 cm) from the tip of his nose to the tip of his tail, about the size of a small donkey.