March 24, 2013 -- The engagement ring the young Napoleon "must have broken his wallet" to buy for his fiancee Josephine shattered expectations today at the Osenat auction house in France when it sold for close to $1 million, Osenat's expert Jean-Christophe Chataignier said.

The winning bidder, who wanted to stay completely anonymous, paid $949,000, almost 50 times the $20,000 Osenat had expected to bring in. Including the buyer's 25 percent commission to Osenat, the total price for the ring was $1.17 million.

"In my wildest dreams, I did not think we would outsell the estimate by more than 47 times," said Osenat's Emily Villane, who led today's auction. "We based the estimates in our catalog on the actual market value of the ring, minus Napoleon and Josephine provenance. It is not our job to tell bidders how much they should pay for the historical premium."

There was intense interest in the ring, she said. In addition to the 300 people in the Fontainebleau auction house, about 50 more international bidders were hooked up by phone.

Osenat, which is in Fontainebleau, outside Paris, also received more than 40 written bids by email from the U.S. alone, she said.

The auction house set up extra phone lines and hired 10 additional people to be prepared for the sale.

"It was 15 minutes of relentless bidding," Villane said. "We opened at 10,000 euros, I raised it to 50,000 euros. From then on it was going up by 10,000. When the hammer went down at 730,000 euros there was a huge applause."

The sale was timed to coincide with the 250th anniversary of Josephina's birthday.

The golden ring is in an 18th century setting called "toi et moi," "You and Me," with opposing tear-shaped jewels -- a blue sapphire and a diamond. The carat weight of the two gems is little less than a carat each.

Osenat already had clues that it had a blockbuster on its hands several days before the auction.

In addition to a great deal of interest from bidders around the world, Chataignier said there were also requests for private spaces a floor above the salesroom, where the superrich could watch and bid without being seen.

The ring may seem unimpressive considering the names attached to it are an emperor and empress, but it actually illustrates Napoleon's passion for his future queen.

"At the time Napoleon was a young and promising officer, but he was not rich. He must have broken his wallet to buy this quality ring," Chataignier told ABCNews.com.

The auction was also held on a unique day, celebrating the 250th anniversary of Josephine's birth, said historian David Chanteranne, the editor in chief of Napoleon I Magazine.

Napoleon met Josephine, (Rose Tascher de la Pagerie as she was known then) in September 1795. She was 32 years old, six years older than Bonaparte. At the time she was the rich and stylish widow of Alexandre de Beauharnais, an aristocrat who supported the French Revolution but died on the guillotine. Her first marriage produced two children, Eugene and Hortense, who Napoleon later adopted.

According to Napoleon's memoirs written at St. Helena, he met Josephine when her son Eugene came to ask him for the right to keep his father's sword. Napoleon said yes, and Josephine invited him to her apartment in Paris to thank him. Napoleon was immediately smitten, and within the first couple months of their relationship had fallen completely in love with her. He wrote about this in his memoirs:

"Everyone knows the extreme grace of the Empress Josephine and her sweet and attractive manners. The acquaintance soon became intimate and tender, and it was not long before we married."

The wedding day was March 9, 1796, but the honeymoon lasted only 36 hours. Napoleon left to lead the French army on a successful invasion of Italy, but during this absence he wrote frequently, sometimes twice a day.

"Since I left you, I have been constantly depressed," one letter says. "My happiness is to be near you. Incessantly I live over in my memory your caresses, your tears, your affectionate solicitude."

"How happy I would be if I could assist you at your undressing," the Emperor writes, "the little firm white breast, the adorable face, the hair tied up in a scarf a la creole."

Napoleon begged Josephine to join him in on his conquest in Milan, but Josephine was often unresponsive, preferring Paris where her kids attended school to the front line in Italy. And the there was her Parisian affair with Lt. Hippolyte Charles.

When Napoleon learned about Josephine's affairs, his letters changed in tone: "I don't love you, not at all; on the contrary I detest you -- You're a naughty, gawky, foolish slut."

The marriage didn't last, but "Josephine continued to treasure the ring and gave it to her daughter Hortense, later Queen of Holland, through whom it came down to her son, Napoleon III and his wife Empress Eugene to whose family this relic ring still belongs," claims Chataignier.

The buyer broke up something of a set. The ring had been on display alongside other historic treasures, including portraits of Napoleon's son and a sword given to the emperor by King Henry IV.