On the run after losing the battle of Grandson on March 2, 1476 against the Swiss, the all-powerful Burgundian Duke Charles the Bold was forced to leave all his baggage with fabulous wealth at the hands of the victors. The most valuable part of this lost treasure was the duke's magnificent pearl-studded hat, in the front clasp of which were set four precious gems—three rubies called the "Three Brothers" and a large triangular blue diamond called the "Great Burgundy Diamond." During the looting of the duke's camp, this clasp disappeared to an unknown place... The duke considered the unique piece of jewelry to be his talisman! Without it, he began to lose his power, lost all other battles, and finally, on January 5, 1477, he met his death on the battlefield under the walls of Nancy. Five hundred years later, these four gems unexpectedly resurfaced and dramatically impacted Aldo Morosini's life. The chain of events was triggered by Aldo's visit to the notary and a tragic incident in the Paris church of St. Augustine...