The London Unidentified Foundry was first discussed by Crellin and Hutton in their excellent analysis of the Wellcome Foundation Mortar Collection. (See: Pharmaceutical History and Its Sources in the Wellcome Collections, Part V, Medical History, Vol XVIII, no. 3., July 1973.) They identified several mortar forms which they ascribed to '.....a large unidentified foundry flourishing in the second half of the seventeenth century'.
The location of the foundry was thought to be at Lothbury and Aldersgate, both locations known to support the metalworking trades. A similar mortar was sold in The Robert Spalding Collection of Mortars, Christie's South Kensington, 12 November 2003, lot 470.