Bishop Arnaldur (1124-52) returned to Norway in 1150 from Gardar, Greenland and was appointed first Bishop of Hamar. He began to build the cathedral, which was completed about the time of Bishop Paul (1232-52). Bishop Thorfinn of Hamar (1278-82) was exiled and died at Ter Doest in Flanders. Thorfinn and many other bishops of the area disagreed with the sitting King Eric II of Norway regarding a number of issues, including episcopal elections. Bishop Jörund (1285-86) was transferred to Trondhjem.
In the aftermath of the Reformation in Norway, the structure was renamed Hamarhus fortress and made into the residence of the sheriff. The cathedral was still used but fell into disrepair culminating with the Swedish army’s siege and attempted demolition in 1567, during the Northern Seven Years' War. Swedish forces had launched attacks into Eastern Norway, capturing Hamar and continued towards Oslo. The Swedes later retreated, torching Hamar on their way, destroying Hamar Cathedral and Hamarhus.
Today the ruins of Hamar Cathedral form a part of the Hedmark museum (Hedmarksmuseet). The ruins of what remain of the Hamar cathedral, were originally built in Romanesque architecture and later converted to Gothic architecture. The distinctive arches in the cathedral ruins are covered in one of the most ambitious construction projects of its kind undertaken by the Norwegian government.References:
The Externsteine (Extern stones) is a distinctive sandstone rock formation located in the Teutoburg Forest, near the town of Horn-Bad Meinberg. The formation is a tor consisting of several tall, narrow columns of rock which rise abruptly from the surrounding wooded hills. Archaeological excavations have yielded some Upper Paleolithic stone tools dating to about 10,700 BC from 9,600 BC.
In a popular tradition going back to an idea proposed to Hermann Hamelmann in 1564, the Externsteine are identified as a sacred site of the pagan Saxons, and the location of the Irminsul (sacral pillar-like object in German paganism) idol reportedly destroyed by Charlemagne; there is however no archaeological evidence that would confirm the site's use during the relevant period.
The stones were used as the site of a hermitage in the Middle Ages, and by at least the high medieval period were the site of a Christian chapel. The Externsteine relief is a medieval depiction of the Descent from the Cross. It remains controversial whether the site was already used for Christian worship in the 8th to early 10th centuries.
The Externsteine gained prominence when Völkisch and nationalistic scholars took an interest in the late 19th and early 20th centuries. This interest peaked under the Nazi regime, when the Externsteine became a focus of nazi propaganda. Today, they remain a popular tourist destination and also continue to attract Neo-Pagans and Neo-Nazis.