Cerulean, also spelled caerulean, may be applied to a range of colours from deep blue, sky-blue, bright blue or azure colour through greenish blue colors. The first recorded use of cerulean as a colour name in English was in 1590. Discovered in 1805 by Andreas Höpfner, the pigment originally referred to as cerulean blue (or corruleum blue) was first marketed in 1860 as "coeruleum" by George Rowney of the United Kingdom. The primary chemical constituent of the pigment is cobalt(II) stannate.