Old Aker Church (Gamle Aker kirke) is Oslo's oldest remaining building and the only remaining church from the Middle Ages. It is assumed that it was built around the year 1150. It is a stone church, built as a three-naved Roman-style basilica.
The church has been pillaged and ravaged by fire several times. The oldest part of the surrounding churchyard dates back to the 12th century. The church has a baroque pulpit and baptismal font from 1715. The tower was built in 1861.
The church was built over an old silver mine, Akersberg which was in use since the early Viking age. The mines are mentioned in the 1170 Historia Norvegiae. The mines must have been the inspiration for a number of stories about the church having hidden silver treasures and even dungeons with dragons.
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.