c. 1819 - Augustus Siebe worked as an instrument maker, watchmaker and silversmith, Siebe & Co. located at 145 High Holborn, London[

1829 - moved to larger premises located at 5 Denmark Street, Soho, London;

1830 - invented the first 'Closed' deep sea helmet;

1868 - Augustus Siebe retires; company managed by son Henry Siebe and W A Gorman

1870 - Siebe & Gorman Company formally founded at 5 Denmark Street, Soho, London; Augustus Siebe's son-in-law, William Augustus Gorman and Henry Herepath Siebe

1894 - exhibited diving apparatus at the Antwerp Exhibition.

1904 - incorporated as a limited company.

1920 - made a camera for use in flooded mines.

1932 - R. H. Davis, inventor of the Davis submarine escape apparatus and of a submersible decompression chamber used in deep sea diving, made governing director.

1941 - relocated to Davis Road, Chessington, Surrey after factory in Lambeth, London destroyed (WW2)

1952 - company made public.

1961 - engaged in development and production of under water television equipment in association with Marconi's Wireless Telegraph Co. Ltd.[

1975 - moved to Cwmbran in Wales, and concentrated on fire-fighter's breathing equipment.

1998 - sold to Norcross Safety Products.

1999 - sold to an Iranian entrepreneur Parvis Moradifor and renamed Air Master Technology Limited followed by final merger with BTR Industries to become Invensys which failed [not to be confused with Invensys software developers].