In fairness, the French dog that won Best of Breed at Crufts 2016 was a more moderate dog:
BUT... he was less than two years old at the time of his win and if you click here you can see what his parents look like. The bulk will come.
Here's another comparison - this time a Mastiff from 1931 alongside another dog that was shown at Crufts this year.
The 1931 dog is a lift from this video from British Pathé, which landed in my Facebook timeline this morning, hence the random Mastiff post on this fine summer's day.