Like College Court, this quadrangle was added by Wren for James II in 1687-8. It was originally a plain gravelled yard, and the fine wrought-iron cage and lamp-post (1722) in the centre protected a well which was provided for watering horses. The roadway with its stone posts and chains was laid out by Soane in 1819.
The Court takes its name from the Light Horse Guards (Cavalry) whose needs were not considered in the original proposal. They were junior to the old soldiers of the Horse Guards (who occupied a pavilion in the East Wing) but senior to the Infantry. Such differences were abolished in 1850.
The North-East wing provided a number of Officers' quarters. This range was heavily damaged, with some loss of life, by enemy bombing in 1918. It was reconstructed in 1923 only to be destroyed again by a V2 rocket in 1945. After the Second World War, reconstruction was long delayed but, in 1964-5 the unsightly ruins gave place to an exact reproduction of the original exterior. The interior arrangements were, however, quite different, and the new building was occupied by additional Long Wards providing 64 additional places. During the construction of the Margaret Thatcher Infirmary the building was used as a temporary Infirmary. The building is now being used as Long Wards and has the first of the new ensuite facilities.