10 Ducats Coronation

Struck to commemorate the Imperial Diet of Regensburg in 1653–54, where Ferdinand III convened the last gathering of the Holy Roman Empire's estates before the constitutional reforms that followed the Thirty Years' War. Regensburg, as the permanent seat of the Reichstag after 1663, had both the prestige and the financial incentive to produce presentation-grade multiples of this kind — distributed as diplomatic gifts rather than circulated currency.

The Fiala reference places this among a small group of surviving Regensburg gold multiples from the coronation series, several of which differ by minor die distinctions now tracked under separate Planck numbers.