’Mysteriekroner’ are a larger group of contemporary, foreign professional imitations/counterfeits of crowns from the Danish-Norwegian mints in Copenhagen, Christiania, and Glückstadt 1653–1679.

All the ‘mysteriekroner’ are machine-struck with square shaped dies, distinguishing them from most of the genuine crowns for that reason alone. They are neither conspicuously underweight nor with much less silver content than the genuine crowns, but their planchets are less well alloyed (clear examples are nos. 57f. and 63). Their technical and artistic appearance varies considerably, and various design elements differ from the genuine crowns.

In the second half of the 17th century, the Danish-Norwegian government knew about the significant counterfeiting/imitation of their crowns, and new monetary policy to solve the problem were enforced in e.g. 1665 and 1687.

The production of mysteriekroner took place in several stages – and perhaps also in different places. There was an extensive production around 1685–1686 of mysteriekroner with the years 1668–1672. The exact place or places of production are not known, but everything points to northern Germany as the place of production, possibly in the non-royal parts of Schleswig-Holstein.

Further info in Sven Aagaard, ‘Mysteriekroner’ – samtidig, udenlandske kopier af københavnske kroner fra Fr.III og Chr.V., Numismatisk Rapport 40, 1994, p. 49–89; Aagaard, Bolt Jørgensen og Märcher, Christian V Glückstadt 1671–1696, 2022, p. 121–127; Aagaard, Bolt Jørgensen & Märcher, forthcoming.