Trefaldighetskyrkan, also called the German Church, was Karlskrona’s German congregation church until 1846. It was inaugurated on 27 June 1709, to designs by Nicodemus Tessin the Younger, who drew on French and Italian Baroque architecture. Palladio’s Villa Rotonda is mentioned as a possible model.

A city fire destroyed the church in 1790. The two brass chandeliers from 1722 and a memorial plaque from 1789, with a relief of the church, were rescued and still hang inside. Reconstruction planning began the following year, using designs by Olof Tempelman. The replacement dome was designed in the Neoclassical style. A ceiling painting by sculptor Johan Törnström and his son Emmanuel makes the dome appear taller than it is.

At its 1802 reopening, the church was named Fredrica Dorothea Wilhelmina, after Gustav IV Adolf’s queen. It received its present name after the king was deposed and the royal family exiled. The church’s website lists an opening from 24 October to 1 November during the World Heritage Festival. That period has ended; the listing gives no later dates.