Bulldog
Don't let their shorter stature fool you. Bulldogs are extremely strong, powerful dogs due to their history as fighting dogs. In 13th century England, bulldogs were used in a horrific sport known as bull-baiting. During these matches, they would fight much larger, more powerful bulls. These fighting bulldogs had aggressive, fierce personalities—a far cry from today's sweet, calm bulldogs. When bull-baiting was banned, bulldog breeders softened their tough personalities, producing the gentle, loving companion dogs that we know today.