Olav's Church was built in the late 1100s, and is a copy of the world's most important church; The Holy Sepulcher's Church in Jerusalem. It also has parallels to Olav's tomb in Trondheim. The ruins show an architecture and medieval thinking in Norway with important spiritual and political currents, at a time when both the crusades and pilgrimages characterized Europe. The round church in Tønsberg was the largest in the Nordic region, and must have been an important attraction of great cultural and spiritual significance, especially since there are few similar churches in Sweden, Denmark and elsewhere in Europe.
Olav Church also served as a grave and baptism church. In the Olav church, the viking king Erling Steinvegg was buried in 1207.
The round church belonged to the Olav Abbey in Tønsberg. It is mentioned for the first time in 1206, and was destroyed in fire, probably during the great city fire in 1536.
The roundhouse, which is the main part of the three rounds, was 23 meters in the inner diameter. The ruins of the church can be seen in the excavations made by the Olav Abbey.
The ruins are located downtown across from Tønsberg Library.