That's a nice and beatiful coin you have, Bonedigger. Indeed, the imperial double-headed eagle is depicted and the coin bears the titles of Ferdinand II, Holy Roman Emperor, but your coin is not Austrian. Your coin has been issued by the Free City of Nürnberg (15 kreuzer KM#60) which is situated in nowadays Bavaria. MON(eta) NOV(a) ARGENT(ea) REIP(ublicae) NORIMBERG(is) means: New silver money of the Republic of Nüremberg. bart
Ben,here's an article about Nuremberg; http://en.wikipedia.org/wiki/Nuremberg .That's a very nice Nuremberg 15 Kreuzer you've got there. There were a lot of German states that were under the nominal suzerainty of the Holy Roman Empire (which is actually a misnomer),as the Empire was neither holy nor Roman. Aidan.
Jerome,it is something to do with the fineness of the silver,plus Ben has turned up the contrasting to show the details. Aidan.