Perhaps the most famous quote about the Mastiff:

"What the Lion is to the Cat the Mastiff is to the Dog, the noblest of the family; he stands alone, and all others sinking before him. His courage does not exceed its temper and generosity and in attachment he equals the kindest of his race. His docility is perfect; the teasing of the smaller kinds will hardly provoke him to resent, and I have seen him down with his paw the Terrier or cur that has bit him, without offering further injury. In a family he will permit the children to play with him and will suffer all their little pranks without offence. The blind ferocity of the bulldog will often wound the hand of the master who assists him to combat, but the Mastiff distinguishes perfectly, enters the field with temper, and engages the attack as if confident of success: if he overpowers, or is beaten, his master may take him immediately in his arms and fear nothing. This ancient and faithful domestic, the pride of our island, uniting the useful, the brave and the docile, though sought by foreign nations and perpetuated on the continent, is nearly extinct where he was probably an aborigine, or is bastardized by numberless crosses, everyone of which degenerate from the invaluable character of the parent, who was deemed worthy to enter the Roman amphitheatre and in the presence of the masters of the world, encounter the pard and assail even the lord of the savage tribes, whose courage was sublimed by torrid suns, and found none gallant enough to oppose him on the desserts of Zaara or the plains of Numidia"
Sydenham Edwards (1800), the Cynographia Britannica