Like many other mints, the Royal Mint issues bullion coins in precious metals, having much higher intrinsic value than their face value. The ten ounce (10 oz) silver coins are denominated as ten pounds (£10).
The coins are legal tender but are not intended for circulation. They are targeted at bullion investors or collectors who appreciate the special editions as pieces of art. The coins are typically "one-year" types usually issued in parallel with smaller denominations with the same reverse designs.
This coin is part of the fourth release of gold and silver coins in the collector series entitled the “Great Engravers", issued to highlight some of the Royal Mint’s great artisans who have made significant contributions to British coinage - many regarded as numismatic masterpieces. The first issue featured Una and the Lion, the second The Three Graces, and the third release was of two parts - one featuring the Gothic Crown reverse, and one one featuring the Gothic Crown obverse (with the iconic Gothic portrait of Queen Victoria).
This release also has two parts: one featuring the reverse of the 1663 Petition Crown, and a second coin featuring the portrait of King Charles II by Thomas Simon which was made for its obverse.
The Petition Crown was a pattern coin produced in 1663 by Thomas Simon, a celebrated English medallist and coin designer. The coin was submitted directly by the artist to King Charles II as a personal "petition" against the contemporary coins designed by the Flemish brothers John and Joseph Roettiers, and for the further Royal consideration that only Simon's designs be used for all future specie now that machine-made currency had been adopted universally for the production of British coinage.
The rivalry between the Roettiers brothers and Thomas Simon resulted from a Royal competition to design this new milled coinage. For unclear reasons, Simon did not submit his trial design in time, resulting in the Flemish engravers winning by default and their coinage being issued for circulation in 1662. However Simon's desire to win back the King's affections resulted in the development of this trial piece the following year. Not only did it dramatically differ from the coins produced by the Roettiers brothers, but also bore his "petition" engraved in 200 letters in two lines around the coin's edge:
THOMAS SIMON MOST HVMBLY PRAYS YOVR MAJESTY TO COMPARE THIS HIS TRYALL PIECE WITH THE DVTCH AND IF MORE TRVLY DRAWN & EMBOSS'D MORE GRACE; FVLLY ORDER'D AND MORE ACCURATELY ENGRAVEN TO RELEIVE HIM [sic].
Even more impressive than the two lines is the fact that the inscription is not all around the edge but only a small part of it, the rest being covered with the kings' monogram of two crossed letters C, crowned.
The adoption of edge lettering on British coinage began under Oliver Cromwell, when Thomas Simon was engraver of dies at the Royal Mint and where he also produced the State Seal of the Commonwealth. The markings were intended to guard against the contemporary practice of clipping or the shaving of precious metal off the edges of a coin for illicit personal gain. At the time of production, Charles II's coinage bore the Latin phrase DECVS ET TVTAMEN (An Ornament and a Safeguard) in relation to this practice. This phrase was still being used on British coins until the revision of the pound coin in 2015. | 
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