Rare plan of the temporary military encampment at Warley Common, near Brentwood in Essex, England, during the Revolutionary War.

Three years after the onset of the American Revolutionary War, in 1778, "a new military emergency arose from the decision of France to form an alliance with the American colonists against Britain. Within a short time, the British militia were called to arms to counter the possibility of a French invasion of England. There ensued a spread of military activity across the country – 'From camps to fleets, from Plymouth to Coxheath' as one contemporary ditty put it. Encampments, ranging in size from a few hundred to several thousand men, transformed the social and economic life of the locality for their duration, and gave rise to what became known as 'Castramania' [the source is too polite here, and does not explain further - ed]. The two largest encampments comprised about 10,000 soldiers and were both inaugurated on Thursday 28th May 1778. One was established on Cox Heath, just south of Maidstone in Kent. The other was situated on Warley Common, south of Brentwood in Essex. Both camps were terminated, nearly six months later, on 11 November 1778 and both were also visited by King George III and Queen Charlotte" (Royal Collection Trust online).

Rarity
We are only able to trace one institutional example: The British Museum. Marshall printed a companion piece 'An Accurate Plan of the Encampments at Coxheath and Warley Common' published on 19th September, 1778, a month after the present plan (see Royal Collection Trust - RCIN 734034.b). The Royal Collection Trust also includes a manuscript composite atlas of plans of the encampments and dispositions of troops in England between 1778 and 1782 - including Warley - by Daniel Daniel Paterson (see - RCIN 734032).