The Nebelung cat is a long-haired Russian Blue cat. The breed was first known approximately 100 years ago, and exhibited at the first British cat shows but forgotten not long after as other breeds became established.

The breed was recreated in the early 1980s with the two registered foundation cats being Siegfried (born 1984) and Brunhilde (born 1985). Siegfried and Brunhilde's mother, Elsa, was a black domestic shorthair, and their father was apparantly a Russian Blue. The kittens in the litter were a mixture of black and blue shorthairs, and surprisingly a beautiful blue longhaired cat - Siegfried. Their next mating produced more black and blue kittens including Brunhilde. It was decided to mate Seigfreid and Brunhilde, and their first litter was born in 1986. The breed was officially recognised by the International Cat Association (TICA) in 1987 under the 'new breeds' category.

Nebelung is a German word meaning 'creature of the mist'. These cats are judged on the same standard as a Russian Blue with the exception of their coat, which is mid-length with a dense plumy tail. They have green eyes, and their fur must be 'blue' (actually dark grey) tipped with silver.

The breed is still uncommon and mainly located in America, but a small number of 'natural' long-haired Russian Blues have been discovered in Russia and there are a number of breeders interested in developing the breed in their theoretical homeland.

Further Reading