In the early 18th century the army of Napoleon took the town, and one of the leading grape varieties, Blue Frankish, comes from the blue colour of the French currency. (Sopron Wine Region, Kertnet.hu.)
My local school contact here in Sopron told me why the wine makers started to call a grape for Kékfrankos (Blau Fränkisch). The story goes as follows. Napoleon's troops liked to drink wine. The wine sellers demanded to get paid in the original currency - blue franc - instead of the war money with a different color (white, I think), due to the uncertainty of a solid backing of the new currency. Here is a quote from a book with the title, Sopron at the Millennium:
The 19th century also brought wars to Sopron, but again, wine saved the town, as the invading troops of Napoleon left without making any havoc in exchange for 200,000 liters of wine... (Page 26.)
I went to to a wine manufacturer called Lővér Pince / Sop-Vin Kft and purchased a bottle of Kékfrankos 2002 for HUF 780. The wine label is painting of two soldiers drinking wine and one of them is holding a blue franc note. I got an old box free of charge as a reminder of the bad times. Állami gazdaság means state owned estate / farm in Hungarian. The designation Kft stands for a private company.
On a related note, check out Free The Grapes! [Via Small Business Trends.]
UPDATE 12/12/04: For more on victories for Soproni wine, read my post, SOPRONI CABERNET SAUVIGNON.