The Weimaraner is a dog that may have been far more rare had it not been for one man breaking the rules of the breeding club that hoped to keep it rare.
The dog was originally called the Weimar Pointer and was first known in the early 19th century. This silver-gray, ghostly looking dog was developed by wealthy Germans in an attempt to create a superior hunting breed for big game. Some say that the German Shorthaired Pointer was a primary bloodline, others say that it was the German Braken and still others claim it was a number of pointers, hunters and even a French hound. However the Weimaraner origin came to be, the dog eventually was used primarily for flushing and retrieving fowl. This wasn't for a lack of ability on the dog's behalf; it was because Germany's forests were shrinking — along with the big game that required them for habitats.
In 1897, the German Weimaraner Club was created; potential members were heavily vetted in order to maintain the dog's purity and status symbolism. Some members were limited to being allowed only sterile dogs so as to further maintain purity, and it was basically forbidden to export the dogs out of the country.
One of those club members who successfully applied to the Club was Howard Knight, a U.S. citizen from Rhode Island. In 1938 (right before the world war that could have killed off this dog), he was given a male and two females. With these dogs, Knight was able to basically save the dog from sure destruction. In the midst of the second world war, in 1942, he led the charge to create the Weimaraner Club of America. That same year, the breed was formally recognized by the AKC; by the following year, the dog was being exhibited at Westminster.
By the 1950s, the Weimaraner's popularity was growing enormously in the U.S. As president of the United States, "I Like Ike" Eisenhower was responsible both for the dog's popularity as well as weakening the breed when he took his Weimaraner, Heidi, to the White House-- the demand damaged the dog by disreputable "breeders" producing watered stock to sell to unsuspecting citizens.
These days, the Weimaraner remains a relatively popular dog, and the AKC lists the breed as being the 34th on the list of the most popular ones. (They came in at number 12 on the same list in the mid-1950s.)