Edmund Russell, a historian from the University of Virginia explains:
The public outcry over the Michael Vick dogfighting case would have shocked Queen Elizabeth I.
Elizabeth, who ruled England 1558-1603, loved animal combat, hosted contests for visiting dignitaries and would have been astonished to see such contests suppressed. Because the United States inherited most of its dog breeds — and attitudes toward them — from England, British history sheds considerable light on the controversy surrounding Vick's kennel in Smithfield, Va.
I recommend the entire piece, particularly if you've never heard of "bull-baiting." In a few concise paragraphs, Russell conveys the social history, evolution, and demise of blood sport in England. Here is the summary version of the story:
There is a direct line from bull baiting at the Smithfield market in London in the early 19th century to dogfighting in Smithfield, Va., in the early 21st. The English created bulldogs good for baits, they crossed bulldogs with terriers to breed dogs suited for fights, and they saw English bull terriers develop into American pit bulls. The ideas of the English humane movement crossed the Atlantic along with those dogs, and they found a receptive audience because the United States underwent similar economic and social changes. The humane movement pointed to the market at London's Smithfield as an example of the behaviors it found reprehensible, and the same is happening today with Vick's kennel in Smithfield, Va.