Not always the best source, but in Wikipedia I read this:
In 1526 the town together with the rest of the Bohemian crown land of Silesia came under the suzerainty of the Austrian House of Habsburg. It remained part of the Piast-ruled Duchy of Legnica until 1675.
Which makes me think it could be set up as a mint in the Duchy of Liegnitz-Brieg.
But then: To help rebuild the town, in 1621 the duke of Legnica granted the right to mint coins, a privilege the town enjoyed for two years.
which sounds more like the town would be its own ruling authority.
So I will mark this as “Started” and see if there is a consensus on which way to proceed.