In 2011, to celebrate the Royal Wedding of Prince William and Kate Middleton, the Royal Mint released a very Limited Issue Royal Wedding Piedfort £5 Five Pound Silver Proof Coin struck in solid .925 Sterling Silver.
The reverse depicts a side profile of both William and Kate and the obverse has the stunning portrait of Her Majesty Queen Elizabeth II by Ian Rank Broadley.
These legal tender coins have been struck to proof quality using specially prepared dies and highly polished blanks.
Piedforts are coins which have been especially struck on thicker than normal blanks.
As their name suggests they are closely associated with France, where from the twelfth century, they were apparently issued by the Kings as presentation pieces.
In Britain the practise of striking piedforts is later and less frequent, but medieval and Tudor examples are known.