 The Concert Hall and Riding School (now the Corn Exchange) were built for the Prince Regent (later George IV) and work started in 1803 to the designs of William Porden.The Concert Hall was the Prince Regent's stables and held 44 horses in a circular stable arrangement with space for the groomsmen on the balcony level above.The stables were based on the Halle au Ble (Corn Market) in Paris which had been built in 1782.