Was founded in 1247 by Sheriff Simon Fitz Mary as the Priory of St Mary Bethlehem outside Bishopsgate. In 1377 'distracted' patients were being treated (i.e. chained to the wall and ducked in water or whipped). In 1547 hospital was fully functioning as a lunatic asylum. In 1675-6 it was moved to a building in Moorfields. By 1800 this building had become unsafe and the hospital moved to a new building, housing 122 patients, in 1815. The building was quickly extended to house the criminally insane. It was further extended in 1835 by a dome and portico to the central block, and a new block to the rear, by Sydney Smirke. The first resident medical officer was only appointed in 1851! In 1864 Broadmoor took over responsibility for the criminal patients. A new hospital was built at Addington and the patients moved out in 1930. The present Bethlem Royal Hospital is at Beckingham.
The grounds were bought by Lord Rothermere who donated them to the London County Council for use as a park. The wings of the building were demolised and the central block of the old hospital became the IMPERIAL WAR MUSEUM in 1936.