One of Napoleon Bonaparte's bicorne hats with great historical value was successfully auctioned at Sotheby's Paris for 1.22 million euros ($1.43 million) on Wednesday. 

The bicorne, once belonging to the legendary European statesman and general, is one of only 19 hats that historians confirmed to have been worn by Napoleon, according to Sotheby's.

The length of the bicorne is 49 centimeters, the front wing size is 15 centimeters and the tail wing size is 20.5 centimeters. The inside of the hat was lined with silk instead of leather materials, because Napoleon was said to be allergic to leather.

What's more rare is that Napoleon wore this bicorne hat when he signed the "Treaty of Tilsit" with Russia and Prussia in June 1807, which makes it historically significant.

Napoleon signed the treaty after leading the French army to defeat the Russian and Prussian coalition forces. The treaty affected the future division of the European continent and at the same time affected the direction of French-Russian relations.

In 1814, Sir Stewart from Scotland bought this bicorne in Germany, and recorded the process in his diary. Sotheby's Paris initially estimated the bicorne at 400,000 to 600,000 euros, before raising the estimate by 100,000 euros. The auction price was 1,222,500 euros, nearly double the estimated price.

Not all Napoleon's bicornes can fetch such high prices. A hat he wore during the Battle of Waterloo in 1815 was auctioned in France in 2018 for 350,000 euros. The estimated value of it is reported to be only 40,000 euros.

Sotheby's Paris held a special auction from September 15 to 22 to commemorate the 200th anniversary of Napoleon's death. The bicorne was one of most important auction items. Paintings, sculptures, silverware and jewelry were also auctioned.