After more than 200 years in the family, the gold-encrusted sword Napoleon carried into battle in Italy will be auctioned off this weekend, across the street from one of his imperial castles.

The intricately decorated blade is 32 inches long and curves gently — an inspiration Napoleon drew from his Egyptian campaign, auctioneer Jean-Pierre Osenat said.

"He noticed that the Arab swords, which were curved, were very effective in cutting off French heads" and ordered an imitation made upon his return, Osenat explained.

The last of Napoleon's swords in private hands, it has an estimated value of at least $1.6 million, according to the Osenat auction house managing the sale.

Declared a national treasure in 1978, the sword still can be sold to a foreign buyer, but the owner must have an address in France and keep the weapon in France five to six months of the year, said Jean-Christophe Chataignier, an imperial expert at Osenat.

The sword was worn by Napoleon — who was not yet emperor at the time — into the battle of Marengo in June 1800, where he launched a surprise attack to push the Austrian army from Italy and seal France's victory, Chataignier said.

After the battle, Napoleon gave the sword to his brother as a wedding present, and it was passed down through the generations, never leaving the family, according to the auction house.

Today the sword is owned by eight direct descendants of Napoleon, including Prince Victor Napoleon, Chataignier said. The auction house will hold the auction in view of Fontainebleau castle south of Paris, constructed by Napoleon as a quiet retreat.

Strong enough for battle, the sword is uncommonly ornate, with geometric designs in gold covering the hilt and most of the blade.

"It's at the same time a weapon of war and a very beautiful work of art," Osenat said.

"It symbolizes more than anything else the power, the force and the incontestable strength of the Emperor Napoleon," Osenat said as he handled the sword. He wore white gloves to protect its steel and gold surfaces.