Napoleon Bonaparte's engagement ring given to his beloved Joséphine in 1796 catapulted well beyond its high estimate of $20,000 to hammer down at more than $948,000 (730,000 euros) at a French auction on Sunday.

Featuring a pear-shaped diamond and blue sapphire set in gold, the 18th-century ring soared well above its estimate based on its historical value. Each gem weighed less than one carat, the auction house stated.

Bidding started at 50,000 euros at the Osenat auction house in Fontainebleau, but quickly escalated. Nearly 300 floor bidders, 50 phone bidders, and dozens of written bids made for a lively auction.

With a 25% commission, the anonymous buyer paid about $1.17 million for the ring.

A wealthy widow with two young children, Josephine was 32 years old when she married Napoleon, who was six years her junior. Their wedding on March 9, 1796, transpired just prior to Napoleon's command of the French army's successful invasion of Italy. He was yet to claim his great fortune and power when he bought the ring for Josephine.

Sold on the 250th anniversary of Josephine's birth, the ring was part of the sale of the “Collection of Prince Victor Napoleon and Princess Clementine of Belgium."

While Napoleon's marriage to Josephine did not last, she handed the ring down to her daughter, Hortense, who gave it to her son, Napoleon III, and it has stayed in the family until now.