4 Ducats

Regensburg was the permanent seat of the Imperial Diet (Immerwährender Reichstag) from 1663, the very year before this coin was struck, making the timing pointed — the city was asserting its financial credibility as a host to the assembled estates of the Holy Roman Empire. Four-ducat pieces were not circulation coinage; they served as presentation pieces and diplomatic gifts, exchanged among the kind of men who were, at that precise moment, convening in Regensburg itself.

The .986 fine gold standard matched the traditional Venetian ducat fineness the issue emulated by name and weight convention.