Many of the terrier breeds that people now lament the "extinction" of never actually existed except in the minds of Victorian picture book makers.
In "The Welsh Terrier Leads the Way," Bardi McLennan recounts the relatively recent origins of the Welsh Terrier.
"In 1800 there were only 15 designated breeds of dogs, and 50 years later there were only 50."
That is of ALL dogs, not just terriers. As late as 1850, a lot of breeds were still not very distinct and several "breeds" were known by different names. For example, in 1851, the Yorkshire Terrier was also known as "the broken-haired scotch terrier." Only in 1870 was a Yorkshire Terrier firmly designated as a breed and breed name. Before then litter mates were often shown in different breed categories -- a situation that occurred with the first prize-winning Jack Russell, which had previously won shows as a "white Lakeland."
The Welsh Terrier and Old English Black and Tan terriers were the same dog -- a type of rough-stock Lakeland dog used in Wales and in the North. These dogs had a fair amount of variation in terms of size and shape, but generally had more color than the "white foxing terriers" preferred in the South.
These rough-coated terriers existed without too much conformity in name or shape (as they still do in the working terrier community in the U.K.), but conformity and a brand name were essential characteristics of Kennel Club registration, and an intrepid history (however fanciful) certainly did not hurt sales.
With the rise of dog shows in the 1860s, the race was on to give every odd-looking dog a name and "improve" them, and terriers were at the top of the list.
One group of Kennel Club breeders decided to embrace a rather ponderous name and an incredible assertion for the brown and black dogs. They were, they asserted, "the root stock" of all terriers in the British Isles, and they were to be called the "Old English Broken-Haired Black and Tan."
The assertion that these dogs were the root stock of all terriers in the UK is rather laughable -- no one know what the "root stock" was, and in any case there probably was no single "tap root," but instead a fine net of "rootlets" that spread far and wide and included a lot of dogs that were not terriers at all -- dachshunds, whippets, beagles, and lap dogs, for example.
In any case, the Welsh were somewhat outraged to have the English bring down a few of "their" dogs and claim they were an "Old English" anything. These were Welsh dogs, and the Welshmen moved quickly to establish that fact. The Welsh got organized quickly, and in 1884 they held the first dog show with classes just for Welsh Terriers in Pwllheli, North Wales with 90 dogs in attendance -- a rather impressive opening shot in this little "terrier war."
For their part, proponents of the "Old English Black and Tan" moniker could not seem to coalesce into a real club; in fact they could not even agree on a name for their supposedly "Old English" breed. Some called it the Old English Broken-Haired Black and Tan Terrier, some the Old English Wire Haired Black and Tan, some the Broken-Haired Black and Tan, and some just "Black and Tan" -- a color-descriptive name that had been used about as often as "white dog" or "yellow hound".
Whatever they might have called the dogs, this new Kennel Club "breed" was in fact a put-up job comprised of a mix of terrier types and they had difficulty breeding true.
In 1885 a survey of the winning dogs in the ring found that all of them were, in fact, first generation dogs, i.e. not Black and Tans out of Black and Tan sires and dams, but Black and Tans produced out of crosses with other breeds. For example, the winner of the first show in 1884 was a dog named Crib that was a cross between a blue-black rough terrier and a famous smooth fox terrier owned by L.P.C. Ashley called Corinthian.
In 1885, the Kennel Club took a Solomonic approach to the name and breed standard for the dog, featuring both dogs at their 1885 show. On April 5, 1887, however, because the English could not get organized, they were dropped from Kennel Club listings, and the new "Welsh Terrier" breed was born, perhaps propelled forward in popularity a bit by the rise of David Lloyd George, the son of a Welsh cobbler, who himself has risen from humble origins to stand should-to-shoulder with the gentry.
The "Black and Tan" terrier is not the only breed that either never existed (or still exists today, depending on how you look at it).
At the same time that one faction was pushing for the introduction of the "Old English Black and Tan Terrier" another faction was pushing for the introduction of the "English White" terrier which, it should be said, has nothing to do with the old English White molosser dog used as a butcher's dog 150 years earlier.
In fact this new dog was really a toy breed created by crossing a small smooth-coated white foxing terrier with some sort of lap dog, which left the resulting progeny with a propensity towards deafness and a bulging "apple head" like that of many modern Chihuahuas.
Both the "Black and Tan" terrier and the "English White" terrier live on in the fevered minds of the breed-obsessed thanks to a book by Vero Shaw entitled "The Illustrated Book of the Dog."
Printed in 1881, right in the middle of the "terrier wars," this book contains about 100 chromo-lithograph plates and engravings of dog breeds that were being put forth as distinct entities at that time. Shaw rather optimistically included the "Black and Tan" as well as the "English White," betting that the political machinations of English Kennel Club dog breeders would prevail.
He was wrong, which is how two "ancient" breeds of terriers, that in fact never exited, managed to appear on the scene for less than 20 years and then disappear altogether.