The Governor of Portsmouth was the Constable of Portchester Castle from the 13th Century to the reign of Henry VIII. Since then Portsmouth had its own military Captain or Governor, who was based in the Square Tower built in Old Portsmouth in 1494 as part of the fortifications to protect the rapidly expanding naval port. The Coats of Arms of former Governors of Portsmouth are displayed on the walls of the Square Tower's Lower Hall. In 1540, the Hospital of St. Nicholas, suitably converted and modernised, became the military centre of the town. Its Domus Dei, now the roofless Royal Garrison Church, became the residence of the Captain or Governor. The Governorship was abolished in 1834.
The Lieutenant Governorship was vested in the General Officer Commanding South-West District from 1793 to 1865, in the General Officer Commanding Southern District from 1865 to 1903 and in the Officer Commanding Portsmouth Defences / Portsmouth Garrison from 1903 until that post was abolished in 1968.[1]