Old Aker Church
Old Aker Church was built as a three-naved Romanesque style basilica and constructed from limestone. It is believed to have been erected by King Olav Kyrre in 1080 as a church for all of Vingulmark, the historic area surrounding Oslo. The grounds of Old Aker Church were originally likely the former site of the regional thing during the pre-Christian period.
Foundations in Norway
The oldest still-existing foundations in Norway are Oslo Cathedral School of c. 1153 and Trondhjem Hospital of 1277.