The Manx has existed as a breed for a very long time. According to Dr. D.W. Kerruish, DVM (Manxland Cattery) in his book The Manx Cat (which was revised in 1965), the breed was known on the Isle of Man two to three hundred years ago. Manx have been recognized by CFA as a breed for many years. My collection of Stud Books goes back to No. 19 in which there are several Manx registered in the late 1920s and early '30s. Since many of them were registered at that time as "details unknown," it is not possible to determine how many of these cats might have had long hair. It is known that many Manx on the Isle of Man were long coated.
Dr. Kerruish is of the opinion that the Manx mutated from the British Shorthair. My personal opinion is that it is impossible to know for certain just when they mutated into a tailless cat. It is very likely that the mutation did occur on the Isle of Man but since many ships docked there, we may never know what was behind the first tailless cat. I am sure that the British Shorthair was involved! Many Isle of Man cats were imported to the US and as there were longhairs in the gene pool on the Isle of Man, it is probable that both coat lengths were behind many of the imports.
Dr. Kerruish did much research on the history of the Manx cat. In his book he states that the earliest reference to the Manx he could find is to cats owned by the famous painter Joseph Turner. He found this reference in the book, Turner's Golden Visions, by C. Lewis Hyde. In 1810, when the painter was 35, he claimed that he had seven cats that came from the Isle of Man.
Jeanie McPhee was kind enough to send me a copy of the article on Manx, written by Frances Simpson, which was published in 1902. This article is quite interesting since it states that at the turn of the century, Manx were shown in Europe with varying degrees of tails. It seems that "stubbies" could compete at that time for championship, and some of them were of top type. Ms. Simpson made remarks regarding the type she expected to see on the Manx when judging. The cats depicted in her article could well be Manx of today, and some of the Manx pictured in Dr. Kerruish's book could also compete with today's Manx. The type we see today in the Manx was apparently seen as far back as the 1800s. Therefore, it is possible that the Manx could be one of the least changed in type of any of the breeds recognized by CFA today.
Both Ms. Simpson and Dr. Kerruish mention in their writings the stump-tailed cats found in Borneo, Japan, and Malaya which are the cats we know today as Japanese Bobtails. It appears that this breed has also been around a long time! Dr. T. Tansanguan of the Faculty of Veterinary Science, Bangkok, Thailand, confirms that the Japanese Bobtail is a separate strain of cat.