The St. Mary's Church (Mariakirken) was probably first built as a small wooden church around 1050. When Håkon V Magnusson became the country's king in 1299, he expanded the church (its 3rd conversion) into the third largest church building in the country at that time. It was only surpassed by the Nidaros Cathedral in Trondheim and St. Hallvard Cathedral (Hallvardskatedralen) 600 meters further up in Oslo. Both King Håkon V Magnusson (1319) and his queen, Eufemia (1312), were both buried in St. Mary's Church. After their remains (skulls) were found in the late 1960s, after identification, they were transferred to the Royal Mausoleum at Akershus Castle in 1982.



The Church of St. Mary burned in 1523, and in 1542 the burnt and dilapidated church was demolished. And after the big fire in Oslo in 1624, the city, on the order of King Christian IV, was rebuilt on the other side of Bjørvika - under the protection of Akershus fortress and under the name Christiania. Then the ruins of St. Mary's Church in old Oslo were covered with soil and used for cultivation. Eventually, the buried medieval city of Oslo went into oblivion, as a "Pompeii of the North".



September 1, 1854, Norway's first railway line was opened between Christiania and Eidsvoll. When the railroad in the 1870s was to lay a new track eastward from Christiania, the train line was planned where archaeologists feared that the ruins of the Church of Mary were hidden. It was not easy to get permission for excavation from the railway company, but in the end, they said yes - and the Church of Mary was found in 1868. This did not stop the railway and the development continued; the train tracks were laid around the ruin.



Two excavations later and a new respect for past history led to the municipality of Oslo purchasing the entire Sørenga area by the state, removing the railway tracks in front of the church and making what we today known as the Medieval Park (Middelalderparken) - it is a park area in the Old Oslo district. The park is located south of Bispegata and east of Sørenggata, down towards the harbor. It was built in 1999 and opened in 2000. The purpose was to give better access to, and a more dignified framework around, medieval ruins. The park is a total of (70 dekar) 17,3 acres (US/UK).



Middelalderparken (The Medieval Park), Minneparken (The Memory Park) (St. Hallward's Cathedral) and Oslo Ladegård thus make up the Nordic region's largest continuous preserved ruin area. Here are several ruins. A water level has been built in the medieval park, marking Alnaelva's original outlet. Down to this, parts of the shoreline from the Middle Ages have been reconstructed.