Rare gold coin designed for dying King George III expected to fetch up to £250,000 at Dix Noonan Webb

An extremely rare Pattern Five Pounds gold coin designed as George III lay dying in 1820 effectively became a commemorative piece for the king. Now one of just 25 thought to have been minted is expected to sell for £200,000-250,000 at an auction at Dix Noonan Webb in London on 16 September 2015.

The coins were given to museums and institutions, as well as to some of the most influential figures of the time. Magnificent creations, they were the last to bear the head of a monarch who had been on the British throne for 60 years and rarely appear on the market. This example is being sold by a lady collector.

“This coin is something very special,” said Christopher Webb, head of the coins department at DNW. “It is a wonderful example of the coin engraver’s art. But it also marks the end of the reign of George III which had seen the loss of the American colonies, the French Revolution, the rise and fall of Napoleon and the birth of the Industrial Revolution. Here beauty combines with history.”

This pattern coin – one produced to evaluate a proposed design but not approved for general release – emerged from the relationship between William Wellesley Pole, Master of the Mint from 1814 to 1823, and the Italian Benedetto Pistrucci, his leading engraver, who came to England in 1815. Thomas Wyon junior, the chief engraver at the Mint, died in 1817 but Pistrucci was barred from formally taking over the post because he was a foreigner. Pole got round this rule by leaving the job nominally vacant, paying Pistrucci £500 a year and giving him the use of the chief engraver’s official residence at the Mint. It was an arrangement that caused some resentment.

No large gold coins had been issued for circulation in England since 1754, before George III had come to the throne, and in December 1819, perhaps realising that the king’s health was rapidly declining, Pole instructed Pistrucci to prepare dies. Although workmen at the Royal Mint laboured through the night to finish them in time, the dies were not completed when George III died at Windsor at 8.38pm on 29 January 1820.

With the king dead, the gold coins could not be minted for general circulation. Instead a small number – thought to be 25 although there may have been 26 – were struck effectively as posthumous commemorative pieces. Six went to institutions such as the Royal Mint, the Bank of England and the British Museum while eight were given to Royal Mint officials. The remainder were acquired by influential figures such as the Marquis of Salisbury, and coin collectors such as the south London brewer Robert Barclay and the museum curator Edward Hawkins. It is uncertain as to whether the Marquis of Salisbury received one or two specimens – hence the debate over whether there are 25 or 26 – but it is more probably the former. Whatever the figure, the 1820 Pattern Five Pounds remains one of the rarest British coins.