A 137-carat diamond owned by the Medicis and the Habsburgs and long thought to have vanished has spent decades in a bank vault in Canada, according to The New York Times. The so-called Florentine Diamond was secreted away when the Habsburg family fled to Canada during World War II, and questions about it in the years since were deflected—until the terms of a 100-year vow were met and the family decided to divulge details of the treasure.“The less people know about it, the bigger the security,” said Karl von Habsburg-Lothringen, a grandson of Charles I, the emperor of Austria-Hungary who transplanted the diamond to Switzerland around the end of World War I. (Charles was a nephew of Franz Ferdinand, whose murder was a catalyst of the war.)After Switzerland the storied diamond went to Canada, and its whereabouts were kept mum in honor Charles’s wife, the Empress Zita, who asked that the secret be kept for a century after her husband’s death in 1922. Over the year, rumors suggested the diamond might have been stolen or sold or recut. But three Habsburg family descendants invited The New York Times to see the diamond, and said they would like to see it exhibited.“It should be part of a trust here in Canada,” Habsburg-Lothringen said of the Florentine Diamond and other jewels with which it has been kept. “It should be on exhibition in Canada sometimes, so that people can actually see those pieces.”The family said it would like to show the diamond in a museum but does not plan to sell it. “It’s an extraordinary achievement to have managed to preserve it for 100 years actually incognito,” said Richard Bassett, an associate fellow of Christ’s College, Cambridge, who called the Habsburgs “the greatest dynasty of modern history.”