This two-coin set is one of the "historic" issues by the Royal Mint combining a newly released coin with a historic coin taken from circulation.
The mint says about it:
"The 2025 edition of The Sovereign pays tribute to its rich history, paying homage to Jean Baptiste Merlen’s Royal Arms design that first appeared 200 years ago. A poignant pairing, this two-coin set includes The Sovereign 2025 and a George IV Sovereign from 1825 - 1830. Both coins feature Merlen’s Royal Arms design on the reverse with the modern remastering of the design on The Sovereign 2025 and the original Merlen ‘shield back’ design on the other, brilliantly preserved for collectors to cherish.
Before emigrating to the United Kingdom, Merlen was a medallist for the Paris Mint. His most famous work during this period was his 1804 design for the Napoleonic medal celebrating the ‘Proclamation and Coronation of Bonaparte as Emperor’, after which the Frenchman began building a reputation as a talented designer.
However, the Napoleonic Wars soon derailed any plans he had to stay in his native land and Merlen left France following Napoleon’s defeat at the Battle of Waterloo. On British shores, Merlen joined The Royal Mint in 1820. Despite his notable design experience in France, he had to contend with both Benedetto Pistrucci and William Wyon, two of The Royal Mint’s greatest talents.
In 1821, just one year after commencing his employment at The Royal Mint, Merlen was tasked with providing a numismatic coinage portrait of George IV. Based on an original work by renowned English sculptor Sir Francis Chantrey, Merlen’s subsequent engraving appeared on the 1823 Double-Sovereign, marking his Sovereign debut."
The modern sovereign coin in the set is in Proof FDC grade, while the historic sovereign is in "fine or better" grade. | 
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