The primary purpose of all the Medway fortifications was the defence of the
Naval Dockyard. This was largely the result of the
Raid on the Medway 12 June to 14 June 1667 when the Nederlandse Staatsevloot (Dutch State Fleet) inflicted heavy damages on Chatham Dockyard. Defences were planned for Chatham Dockyard from 1708 and land was then acquired by two
Acts of Parliament. These were the Fortifications Act 1708 and the Fortifications Act 1709. The land was surveyed in April 1715 by
Duke of Marlborough. The first plan of defences was an
enceinte (ring of fortifications), from Gun Wharf,
Chatham, to north of the village of
Brompton. From January 1755 to August 1755, the 'Prince of Wales'
Bastion, 'Prince Williams Bastion', 'Kings Bastion', 'Prince Edwards Bastion', 'Prince Henry's Bastion' and the 'Prince Fredericks Bastion' were all built. The fortifications were designed in January 1755 by Captain John Peter Desmaretze of the
Board of Ordnance and consisted of a earthwork ditch and a parapet. In June 1757, an infantry
barracks (for a troop
garrison) was built to man the defences. Amherst Redoubt later became Fort Amherst. Each was equipped with 14
42-pounders, 10 9-pounders, 8 6-pounders and 2 4-pounder guns. In February 1779, during the construction, workmen found an existing foundation of a
Roman building. Several finds, including pieces of Roman brick and tile, were made. Roman coins were also found, including one of the
Empress Faustina, and one of the
Emperor Claudius. The finds were recorded by Rev.
James Douglas, working as Lt Douglas with the Royal Engineers 'North Lincs Militia, who later wrote a book describing all of his archaeological research -
Nenia Britannica. During the
Napoleonic Wars (1803–1815) the
Chatham defences were enlarged and considerably strengthened. Further batteries were added (such as the Cornwallis Battery) and the ditches
revetted (lined with brick), His plan for the Chatham Lines, drawn by Joseph Heath and dated January 1755, is kept at the
British Museum. Also, from September 1802 until June 1811, prisoners, mostly convicts from
St Mary's Island, Fort Amherst has been described by
English Heritage as the most complete
Napoleonic fortification in Britain and as such has great national historical significance. Fort Amherst was still in use during the
Second World War when it served as an Air Raid Warning Command Post for the
Air Raid Precautions (ARP) and the
Royal Observer Corps (ROC). It later underwent restoration to make more areas accessible to the public. An attempt was made by the Royal Engineers, to convert Fort Amherst into a display ground for their military vehicles, as an offshoot of the
Royal Engineers Museum in Gillingham, but this was prevented by a lack of finance. ==Current use==