From the history of the breed: 
The Kennel Club recognised the breed of Bullmastiff in 1924 (at that time the breed name was written as "Bull-Mastiff"), but the breed itself was formed much earlier. The dog was called "The Keeper's Night Dog", "Mastiff mixed with Bulldog", "big Bulldog" or "small half-breed Mastiff". 
Country of origin: England.

General appearance: 
Proportionally built, showing great strength, but not bulky; strong and active. 
Height and weight: 
Height at the withers: males 25-27 inches (63,5-68,5 cm); females 24-26 inches (61-66 cm). 
Weight: males 110 pounds (49.9 kg); females 108-110 pounds (41-49 kg). 
Shape: 
Square like. The index of the format is 102-104. Coat: Short and rough, tightly fits the body, protects the dog well from bad weather conditions. 
Color: 
Any shade of brindle, fawn or red, but it must be clean and without any tinctures. Small white spot on chest is permissible. The presence of white spots in other places is a fault. A dark mask with a distinctive edging around the eyes is required. It creates a special expression. 
Head: 
Large and square when viewed from any angle, when alert there are few wrinkles appear, and disappear when calm. The girth of a skull should be equal to the height at the withers. The skull is broad and deep with well developed cheekbones, the stop is strongly expressed. The muzzle is short; the distance from the tip of the nose to the stop is one-third of the total head length from tip of the nose to the occiput.

Ears: 
V-shaped, hanging, widely and highly set on the line of the occiput, make the skull square in shape, that is very important. The ears should be small and of a darker color than the whole body; when alert the ends of the ears are at the eye level. "Rose-shaped" ears are not allowed. 
Eyes: 
Dark or hazel in color, medium in size, widely set (at the width of the muzzle), separated by median sulcus. Light or yellow eyes - is a fault. 
Teeth: 
Level bite, can have a small overbite, but it is not desirable. Fangs are large, set wide apart; other teeth are strong, straight, properly set. 
Neck: 
With a good curve, moderate in length, very muscular, the girth is almost equal to the circumference of the skull. 
Body: 
The back is short and straight, makes the dog look compact, but not so short to limit the movement of the dog. Soft and sunken back - is a fault. 
Chest: 
Broad, deep, with deep chest bone.

Tail: 
Set high, strong at the base, tapering at the tip, reaches the hock joint, carried straight or slightly curved, but not in the manner of a hound. A broken tail is a fault. 
Limbs: 
Forelimbs are strong and straight, widely-set, frontal part is straight. The pasterns are strong and perpendicular. 
The hind limbs are strong and muscled with well expressed calves, what indicates on strength and activity, but without traces of clumsiness. Hock joints are slightly sloping. 
Attractive features: 
Bullmastiff is a silent, menacing guard who has a great strength, dexterity, speed and determination. He is a wonderful friend of a family, kind and reliable. He is a massive, a bit stocky, but not bulky dog. This dog breed is a combination of nobility with kindness, courage with gentleness.