This piedfort was minted in 1673 in a temporary mint in Amsterdam. The Holland provincial mint was moved from Dordrecht to Amsterdam due to the French invasion in 1672. Simply put, Amsterdam was a safer location.

The Amsterdam piedfort ducat was the only date of the Holland (province) gold ducats minted outside the official mint (!). They were minted in a private atelier of Christophel Adolphi in Amsterdam.

The Adolphi workshop was chosen because he had mint presses which was a distinct advantage. The official mint was still minting ducats the old way, with a hammer. What makes this coin special – in addition to its condition, rarity and provenance – is the lettered edge. It reads -  “D : GEDACHTENIS . V : D : MUNTE . V : AMSTERDAM”, translation – “In memory of the Amsterdam mint”.

(source: cngcoins.com)