After London Bridge and Westminster, Blackfriars Bridge was the third bridge to be built across the Thames in the 18th century. In this preparatory sketch by Elias Martin (1739–1818), Blackfriars is shown from the southbank of the Thames during the final stages of its construction in 1769. The sketch is prepared on a grid-lined sheet for scaling up. An inscription at rear reads ’painted for Sir John Boyd, and the architect of the bridge’, indicating that at least one if not two paintings were produced from this and possibly other sketches. Sir John Boyd (1718–1800) was a powerful sugar merchant and vice-chairman of the British East India Company and Robert Mylne (1733–1811) was the Scottish architect and engineer who designed Blackfriars Bridge.