Button with princely crown or princely hat and the monogram "W" around 1750 / 1800.
Theory 1: Duchy of Württemberg - military button - "W"=Württemberg
Theory 2: Electorate of Würzburg - military button - regiment of the prince-bishop of Würzburg imperial troops
Theory 3: Austria - military button - the monogram stands for regiment owner: ?
Found:
Germany: - / Czech Republic: 1. Jindřichův Hradec - Neuhaus and Sobieslau - Sobieslau / Sobeslau (Jihočeský kraj - South Bohemian Region), 2. Litoměřice - Leitmeritz (Ústecký kraj - Ústí nad Labem Region), 3. Hradec Králové - Königgrätz (Královéhradecký kraj - Hradec Králové Region) / Poland: 1. okolice Lutynia - Leuthen [Battle] (Województwo dolnośląskie - Lower Silesian Voivodeship), 2. Województwo lubuskie - Lubusz Voivodeship / Serbien: got from Srem District
Any further information about the found location is welcome!
Further theories are welcome. The button collector community will be very grateful if you can contribute to the solution of the riddle.