Israel Sigmund Greenberg (c.1845-1926) was born in Russia, of Jewish parentage.  He was the son of Menachem Mendel Greenberg and Bunne Dominitz.  

Israel Sigmund became a jeweller at Birmingham. In 1870, he was naturalized. By 1881, his address was Frederick Street, Birmingham. In 1884, he registered a silver mark in London.  By 1886 he was trading at Bennett’s Hill; then in 1889 he was based at Vyse Street.  He advertised as I. S. Greenberg & Co, jewellers, silversmiths, watch and clock manufactures and importers, plate and bullion dealers (Watchmaker, Jeweller & Silversmith, 1 July 1891).   In 1893, he moved to another address is Birmingham’s jewellery quarter: Great Hampton Street (at the corner with Hall Street), where he initially fitted out a showroom.  He registered another London silver mark in 1902. The enterprise became a private limited company in 1909.

Israel Sigmund Greenberg, Rotten Park Road, Edgbaston, died on 18 October 1926 at Bournemouth.  He left £29,711 and was buried Witton Jewish Cemetery, Birmingham.  

Sigmund had three sons in the family silversmith business: Ellis Jacob Greenberg (1879-1931); Herbert Simeon Greenberg (1881-1966); and Montefiore (‘Monty’) Solomon Greenberg, later Louis Greenhill (1884-1943). Sigmund, Ellis, and Simeon became partners in another silver-plate firm in Great Hampton Street:  Ellis & Co (Birmingham) Ltd. Simeon Greenberg wound up I. S. Greenberg & Co in 1943, but it was resurrected and traded under Simeon until another liquidation in 1960. It then became part of Barker Bros, Birmingham: trading as Barker Ellis Silver Co Ltd.