The Board of Ordnance
From the end of the middle ages until the mid-19th century, the key organisation in the defence of England's borders was the Board of Ordnance. The term 'ordnance' covered all military and naval supplies, from weapons and ammunition to wagons and tents. The Board's responsibilities also included the construction and maintenance of defensive structures, such as forts and batteries.
Although the Board of Ordnance was not formally instituted until 1597, a Master of the King's Works, Guns and Ordnance had been appointed by Henry V as early as 1414. The first holder of the title was the king's chief engineer, Master Nicholas Merbury. Since the Tower of London had long been the headquarters of the king's engineers, the Tower was the obvious home for the new Master of Ordnance. Under Henry VIII, the Master of Ordnance's office was enlarged and reorganised, with subordinate officers appointed to particular duties: a Lieutenant-General, Storekeeper, Surveyor and Clerk of Deliveries
By the 18th century, the Board consisted of a Master-General and four Principal Officers presiding over an organisation divided into civil and military sections. The Board and the Civil Establishment were housed in the Ordnance Office at the Tower of London, the country's chief arsenal.
This coloured plan of the Tower, drawn in 1725 to a scale of 80 feet to an inch, shows the Office of Ordnance on the south side, flanked by large storehouses and a barracks.