Four Nelson is one of the ring of polygonal forts built on the landward side of the naval base at Portsmouth in the 1860s, when the British government under Lord Palmerston (1784-1865) feared an invasion from France. It was named after a nearby column erected in 1807 in honour of Horation, Lord Nelson (1758-1805), victor of the Battle of Trafalgar. Construction began in 1860, but the first soldiers did not move in until 1871, and the first big guns arrived two years later. The line of forts was obsolete before it was completed and was often called Palmerston’s folly. Fort Nelson served as a barracks for newly recruited soldiers in the First World War and as a centre for Anti-Aircraft defence in the Second World War. It subsequently fell into disrepair but was purchased by Hampshire County Council in 1988 and since 1995 has been the home of the large exhibits, chiefly artillery pieces, from the Royal Armouries Museum, formerly held in the Tower of London. The collection of 350 artillery pieces includes guns from all over the world, many of them acquired during the imperial wars of the 19th century. There are examples of heavy guns used by the British army from the late middle ages until modern times. Live firing demonstrations take place daily. The Royal Armouries holds databases on cannon made in Great Britain and held in castles, fortified sites and museums in many parts of the world.