In Königsberg (Prussia, Germany), in 1930, two blue males were born from a Russian blue father and a mother who was described as a brown Angora. Both Nest Brothers had a curly coat. One of them, Munk, is known to have walked uncastrated in adulthood. In that way, he may have contributed to the spread of the gene that causes curling hair.
The curly Munk has become fourteen years old. Much later, after the Second World War, curly cats were discovered again in the 1950s in Berlin. It is unknown if these cats are descendants of Munk. Since many people from Königsberg and the surrounding area have worked in the war years in Berlin, this could be an option. The documented history of the breed German Rex, however, really starts in the year 1951. In that year, the veterinarian Dr. Scheuer-Karpin found a black cat with a curly coat, which stopped at the site of a hospital. When she looked closer at the animal, it appeared to have only a soft, ruffled undercoat, similar to that of the Cornish Rex, and no (harder) outer coat. At the time Dr. Scheuer-Karpin took the kitten in her house, it was probably already four years old. The vet called her foundling Lämmchen.
Lämmchen was covered by an ordinary house cat called Bläckie. The kittens that were born from them all had a normal coat. Thereupon, Dr. Scheuer-Karpin wanted Lämmchen to be covered by a son of her, to see if the curly coat was caused by a recession gene. However: Lämmchen only accepted Bläckie as a partner and was only allowed to cover after his death by her son Fridolin. That was in the year 1957, Lämmchen was then at least ten years old. From this mating four kittens were born: two of them had a normal coat and two had a curly coat. Thus it was found that the Krullerige coat was after Lämmchen compare and also inherited recessive.
Dr. Scheuer-Karpin wanted to capture this mutation in a new breed, but she received little acclaim in her own country. Logically, the timing where this took place. Some descendants of Lämmchen came to England where they were used to insert new blood into the Cornish Rex – the gene that caused curling hair to the German Rex, was the same as that of the Cornish Rex.
Yet in Germany, especially in East Germany, there were a few people who wanted to maintain the young breed. In the period, both domestic cats and Persians and Devon Rexes were crossed in the German Rex to widen the gene base. That was also necessary because there was little other material behind the (then) Iron Curtain. Nevertheless, new curly cats were discovered every now and then, which were involved in the breeding program. In 1970, the German Rex cat Jeanette Kom Grund was exhibited at a large exhibition in Prague (Czech Republic). In 1973, some German Rex cats were exported to West Germany and a little more people started to use it to preserve the breed. Although the breed was recognized by the Fifé in 1983, the breed is still in full construction today. In 2002, the first breed club for this race was established in Germany.
Source: The Big cat encyclopedia – Esther Verhoef