The Royal Armouries is the oldest museum in the UK. The first recorded weapons are during the reign of King John (1199–1216) and by the reign of Edward III it had become an arsenal to supply the English army and navy. The museum started to take shape during the Tudor period, and after the death of Henry VIII in 1547, the contents of other palace armouries including Henry's own equipment came to the Tower.
Royal Armouries, HM Tower of London
London
EC3N
http://www.royalarmouries.org/extsite/view.jsp?sectionId=82
March to October: Monday to Saturday, 9am-5pm. Sundays, 10am-5pm November to February: Tuesday-Saturday, 9am-5pm. Sundays, 10am-5pm
Adult £15; children £9.50; senior £12; family £43