"It's an exceptional piece," enthuses Cécile Colonna, director of the Department of Coins, Medals, and Antiques at the National Library of France. A gold coin minted during the reign of Charlemagne, a rare piece discovered by a metal detector enthusiast and later seized by Customs, has joined the public collections at the National Library of France, along with a world map printed in Paris in 1660. Only four known examples of such a coin remain. This coin was minted in Uzès (Gard department, southern France) at the end of the 8th or the beginning of the 9th century and has survived to the present day after spending a long time buried underground. IMAGES AND SOUNDBITES