The highlight of the “Royal & Noble Jewels” sale is this historic diamond brooch/pendant — originally crafted around 1810 and believed to have served as a hat ornament for Napoleon. The design features a central oval diamond weighing 13.04 carats, encircled by nearly one-hundred old mine- and mazarin-cut diamonds arranged in two concentric rows.

The story behind the jewel is as dramatic as the gem itself. After Napoleon’s defeat at the Battle of Waterloo in June 1815, he fled the battlefield and abandoned a carriage stuck in the mud that contained his possessions — including this brooch. The piece was subsequently seized by the victorious Prussian army and presented to Friedrich Wilhelm III of Prussia three days later as a trophy of war. For more than two centuries it remained in ownership of the House of Hohenzollern (the former imperial German dynasty) before passing into private collection.

This will be the brooch’s first appearance at public auction. The estimate published by Sotheby’s places its value at approximately CHF 120,000-200,000 (USD 150,000-250,000).

Sotheby’s catalogue adds further background: “This circular jewel … can be conclusively identified as a hat ornament left behind by Napoleon in his carriage when retreating from the battlefield at Waterloo.” The provenance continues: “In 1815 King Friedrich Wilhelm III of Prussia was gifted the round piece of diamond jewellery and stated he would keep it ‘as a curiosity and a permanent souvenir with the crown jewels’."