 During the First World War, the building was requisitioned by the War Office to create the 4th Northern General Hospital, a facility for the Royal Army Medical Corps to treat military casualties.Lincoln Cathedral choristers were educated at the school until the mid-20th century; the Cathedral School for Boys, now known as Lincoln Minster School, subsequently took over that role.On 22 July 1941 an RAF Handley Page Hampden crashed into the boarding house of the Girls' High School on Greestone Stairs, killing Miss Edith Catherine Fowle, a languages teacher, as well as the occupants of the aircraft.