After the collapse of the Baker family fortunes following the civil war (1642–1651), the building declined in importance. Horace Walpole visited in 1752: "yesterday, after twenty mishaps, we got to Sissinghurst for dinner. There is a park in ruins and a house in ten times greater ruins." During the Seven Years' War, it became a prisoner-of-war camp. The historian Edward Gibbon, then serving in the Hampshire militia, was stationed there and recorded "the inconceivable dirtiness of the season, the country and the spot". It was during its use as a camp for French prisoners that the name Sissinghurst Castle was adopted; although it was never a castle, there is debate as to the extent to which the house was a fortified manor. In 2018 an important collection of historical graffiti drawn by some of the 3,000 prisoners was uncovered beneath 20th-century plaster.