Coins are an extraordinary window into history. For example, at New York’s International Numismatic Convention next month, they’re auctioning an Austrian Ducat struck by the leader of the Counter-Reformation movement who kicked out all of the Protestants from Salzburg. With remarkable detail, the 1594 Ducat shows a symbolic Catholic tower lashed by a great storm. High estimate $40,000.A total of 2,945 lots of world and ancient coins and paper money will be offered during three sessions, Jan.4-9. Continuing a tradition, Stack’s Bowers and Ponterio will again serve as official auctioneers. The convention is headquartered at the Waldorf Astoria. The paper money session will be held Jan.9 at Stack’s Bowers Galleries on West 57th Street.