Extra-ordinary tax to cover expenses for equipment and dowry when a princess should marry. The description "prinsessestyr" became normal from the 1660's; earlier it was called "bride-tax" or "mistress-tax". Prinsessestyr was collected for the last time 4 nov 1749.
The tax of 1680 was collected because the Swedish king Karl 11 married Ulrikke Eleonore, the sister of the Danish-Norwegian king Kristian 5. The 5 year old, bloody war between Sweden and Denmark-Norway, called "The Skåne-war", was terminated in September 1679, and the marriage was a direct consequence of the peace-treaty.