Colour and coat variations have been part of the Russian Blue since the breed was first developed in the nineteenth century. Although breeders at the time did not recognize these variants, selecting for blue shorthairs, the genes persisted and more importantly, the desire among cat fanciers for a longhaired variant remained. In the early 1980s, an American cat fancier obtained a number of blue longhairs and in consultation with a known geneticist began developing the Nebelung using these longhairs and pedigreed Russian Blues. As the USSR opened up to outside influence in the late 1980s, the Russian Blue was redeveloped in Russia using select western European cats, domestic cats, and Orientals—these cats were also used in development of the Nebelung, creating a more moderate cat than the Russian Blue itself.

Like the Russian Blue, the Nebelung is an extremely rare breed popularly claimed by shelters and pet owners. In reality, these cats are often common blue longhairs that, while striking, are entirely separate from the pedigreed Nebelung and should not be confused.

Type & judging remarks
The Nebelung is a cat of semi-foreign build, with a svelte but not Oriental look. The head is a medium wedge blending into a blunt muzzle, and has a two-plane profile with a Mona Lisa smile. The long hair softens the lines and makes the silver-tipped blue coat look like mist or fog.