Both the Irish Wolfhound and the Great Dane can be more than six inches taller than the English Mastiff, but (in the words of Wikipedia) they are "not nearly as robust."
According to Wikipedia, "The greatest weight ever recorded for a dog, 343 pounds (155.6 kg), was that of an English Mastiff from England named Aicama Zorba of La Susa, although claims of larger dogs, including Saint Bernards, Tibetan Mastiffs, and Caucasian ovcharkas exist. According to the 1989 edition of the Guinness Book of Records, in March 1989, when he was 7 years old, Zorba stood 37 inches (94 cm) at the shoulder and was 8 ft 3 in (251 cm) from the tip of his nose to the tip of his tail, about the size of a small donkey. After 2000, the Guinness Book of World Records stopped accepting largest or heaviest pet records."
In its introduction, Wikipedia tells is that the English Mastiff "is referred to simply as the Mastiff by national kennel clubs, including the United Kingdom's Kennel Club". This is not very helpful to quizzers, who need to distinguish this breed from other types of mastiff – especially the Great Dane, which is also known as the German Mastiff.
© Haydn Thompson 2020