On Tower Hill, to the north-east of the Tower, is the Royal Mint, built in 1810-12 from the designs of John Johnson, with a gatehouse by Sir Robert Smirke, but since then considerably extended. It succeeds the old Navy Victualling Office, which was built soon after 1562 on the site of the Cistercian abbey of St. Mary of Graces, founded by Edward III. in 1350, and said to have been called Eastminster, as rivalling in importance the Benedictine Westminster. In the Mint are struck the gold, silver, and bronze coins current in the United Kingdom, as well as coinages for various colonies, naval and military medals and decorations, the Great Seals of the kingdom, the seals of the government offices, etc. The Mint is controlled by the Deputy Master, for since 1870 the old office of Master of the Mint, held by Sir Isaac Newton in 1699-1727 and by Sir John Herschel in 1850-55 has been merged in the dignity of Chancellor of the Exchequer.
Coins have been struck in London probably from Roman times. Under the early Norman kings there were also about seventy provincial mints, but the twelve that survived to the reign of Edward III. were consolidated by that monarch, placed under the direction of the mint in the Tower of London, and eventually suppressed. The Royal Mint has branches at Ottawa in Canada and at Sydney, Melbourne, and Perth in Australia; and there are mints at Calcutta and Bombay.
Permission to visit the Mint is granted, on previous written application, by the Deputy Master. Visitors are shown the interesting processes of melting and rolling the metal, cutting and annealing the blanks, and striking and weighing the coins. The presses can stamp coins at the rate of about 100 per minute; 1,000,000 coins (to be increased to 1,500,000) can be struck in a day. The machines for weighing the gold and silver coins are exceedingly ingenious. The interesting and conveniently arranged Museum of Coins comprises a representative series of British and Colonial coins from Roman times downward; specimens of Maundy money and other special coinages; naval, military, and commemorative medals, etc. Here are shown also the punches and matrices for the Great Seals, and impressions of the Great Seals from the reign of King Offa of Mercia (died 796) to the present day.