In 1999 to celebrate the Millennium, the Royal Mint released a very Limited Issue Anno Domini £5 Five Pound Silver Proof Coin struck in solid .925 Sterling Silver.

At midnight on 31 December 1999, there will be a vital moment shared by the thousand years past and the thousand years that stretch head.
It is this portentous moment that is captured on the reverse of the United Kingdom, Millennium £5 Five Pound Silver Crown Coin.

Poised on the threshold of time, the British Isles are shown carefully positioned on a symbolic clock face, the hands set at the crucial twelve o'clock between the dates 1999 and 2000 and appropriately pivoted at Greenwich, the Prime Meridian of the World since 1884 and thus the source of World Time.
The significance of the moment is emphasised in the words chosen for the edge inscription WHAT'S PAST IS PROLOGUE taken from Shakespeare's 'The Tempest'. They appear as raised edge lettering around the edge of the Coin, a feature popular with collectors but rarely seen in recent years.
The obverse design is Ian Rank Broadley's portrait of Queen Elizabeth II.
These legal tender coins have been struck to proof quality using specially prepared dies and highly polished blanks.