The construction Haga Church (Hagakyrkan) began in 1856 and it was finished in 1859. The church and the pulpit were designed by architect Adolf W. Edelsvärd. The church represents the Gothic revival architecture style.
The first organ was installed in 1861 by the Danish firm Marcussen & Søn for the price of 20 000 Swedish crowns. It was rebuilt in 1911 (pneumatic action) and 1945-1951 (electric action) by the Magnusson organ building firm. It was restored to close to original condition 2002-2004 by Åkerman & Lund.
References:The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.