The first St. John's dog was said to be brought to England in or around 1820, but the breed's reputation had already spread to England; there is a story that the 2nd Earl of Malmesbury saw a St. John's dog on a fishing boat and immediately made arrangements with traders to have some of these dogs imported to England. These ancestors of the first labradors so impressed the Earl with their skill and ability for retrieving anything within the water and on shore that he devoted his entire kennel to developing and stabilising the breed.
The progenitors of the Labrador retriever were actually from Newfoundland and Labrador exceptionally, the breed known as the Newfoundland was created near the same time in Labrador. The two breeds' names and origins were mixed once moved into England and both North and South America. The dog from Labrador became the large, long-furred dog we see and know today, and the dog from Newfoundland became the Labrador.
A vigorous dog may or may not be high-energy, but everything he does, he does with vigor: he strains on the leash (until you train him not to), tries to plow through obstacles, and even eats and drinks with great big gulps. These dynamos need lots of training to learn good manners, and may not be the best fit for a home with young kids or someone who's elderly or frail. A low-vigor dog, on the other hand, has a more subdued approach to life.