It was sovereign territory at Baldwin’s once more earlier this month when they took £430,000 for an Edward VIII gold proof example dated 1937 and £320,000 for an Elizabeth II example dated 1953.
Both were from the Hemisphere Collection of Gold Sovereigns - part of a three-day 2663-lot sale in London which totalled £4.8m, with £1.25m selling online.
The sale follows the auctioneers' record-breaking auction series which dispersed of the Bentley Collection of British gold sovereigns in 2012 and 2013. That included a very rare sovereign of the Perth Mint struck in Australia in 1920 - only three are known to exist - that set a record price of £780,000 in September 2012 at Coinex.
Of the greatest rarity in the modern Proof Sovereign series, the Edward VIII example which sold on May 8 is the only single coin available to collectors and this is only the third time it has been sold at auction since its first appearance in the saleroom in 1984. There is only one other in private hands - even the Bentley Collection did not include one.
As with other artefacts linked to the reign, the king's early abdication and the subsequent scrapping of the dies rendered proofs from the series as true rarities.
The 1953 Elizabeth II example was not issued for sale to private collectors, and this is only the second time that one has appeared at auction.