Just got this from Andreas Fenzl (MA-Shops) Mainz/ Ezbistum AV Dukat 1645 Mainz Mint 3.41g. 22mm. .986 12h Slg.Walther 284 Fr.1654 Anselm Kasimir Wamboldt von Wollrath Kurfürst / Mainz obv: Tablet within Laurel Wreath Crowned Arms within Laurel Wreath ANSELM CASIMIR D:G:A.R.EP MO:S:R:IER G:AR.CAE This coin is finest ex. known/ a bargain for 1900 euros....
Mainz was an Archbishopric in what is now NW Germany. A sort of Church ruled City State. I was born in same area in Jülich. Formerly the Herzogtum (Duchy) of Jülich Cleves Berg.