Constantine I A.D. 2007 30mm 9gm Obv. CONSTANTI NVS PF AVG Rev. KONSTANTINTHALER 2007 SPARKASSE TRIER CITY-INITIATIVE TRIER e. V. The reverse is the Porta Nigra, an ancient Roman gate for the city of Treveri, now called Trier. This 10 euro coin was issued by a bank in Trier, Germany, to mark the 1700 year anniversary of Constantine's residence in that city, and was legal tender in the city until 31 March 2008.
Nice piece; I have one of those too. :thumb: As for why these were issued - in 2007 Luxembourg was European Capital of Culture; not just the city but an entire region covering Luxemburg (the country), Wallonie (BE), Lorraine (FR), Saarland (DE) and Rhineland-Palatinate (DE). The big "Constantine" exhibition in Trier was Rhineland-Palatinate's main contribution to that event, and the City Initiative with the local savings bank issued the Konstantinthaler on that occasion. The initial mintage was 10,000 (made by a private mint in Bochum, North Rhine Westphalia) and those were sold out pretty quickly. Then 20,000 more were made - people could use them for payments or would collect them. The Konstantinthaler was not legal tender of course but most local businesses accepted it, until 31-Dec-2007, like a €10 note. Until 31-Mar-2008 it could be redeemed at the Trier savings bank. Christian