Arthur Octavius Windsor ran a coffin furniture factory in Birmingham, UK in the 1880s, but was a keen banjo player in his spare time. Windsor began to make banjos in part of his factory. These proved to be popular and he opened an instrument factory (the Castle Works) in Newhall Street, Birmingham in 1890. The head office, show room and metal part manufacturing was in the Castle Works and the saw mill and wood working factory was in the Hampton Works on Mott Street. By the 1930s Windsor was producing thousands of instruments each year including banjos, zither-banjos, banjolins and mandolin-banjos. They also exported widely and made their cheaper instruments available for other retailers who branded them with their own names. In 1940, however, the factory was destroyed in an air raid and the company closed.
Source: The Banjo Story. A.P. Sharpe (unpublished)