Bonhams' Fine Watch auction on June 11 in London will feature a pocket watch owned by George IV, featuring the royal coat of arms.
Produced in gilt-brass, the Josiah Emery pocket watch dates to 1785 - when George IV was still the Prince of Wales - and is estimated at £60,000-80,000 ($100,629-134,172).
Emery is credited with being the world's first watchmaker, as he invented the lever escapement in the 1780s, a crucial development in making portable timepieces.
Also featuring in the auction is a gold, enamel and split pearl pocket watch owned by Empress Marie-Louise, Napoleon Bonaparte's second wife and empress of the French between 1810 and 1814.
An "exceptionally pretty" piece, the pocket bears the Napoleonic insignia of a bee on one side, with the cipher "ML" for Marie-Louise on the reverse. It was presented to a four-year-old Emilie de Pellepra at Cherbourg harbour in 1813.
It has remained in the same family collection for over 200 years, with this the first time it has ever been offered for sale.
Empress Marie-Louise was drafted in as Napoleon's great love and first wife, Josephine, was unable to provide him with a child. She reigned alongside Napoleon for four years, before the 1814 Treaty of Fontainebleau saw her established as the Duchess of Parma.
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