St. Mary's Church Ruins, Oslo

Saint Mary's Church, situated in Oslo, was a medieval place of worship. The remnants of this church now lie within the Medieval Park (Middelalderparken) near the Sørenga neighborhood, which is part of the Gamlebyen borough.

Constructed gradually in stages from stone, Saint Mary's Church underwent its final enhancements in the 14th century. An extensive renovation during the 1200s introduced a new Gothic choir to the church's architecture. A significant reconstruction in the 1300s expanded the church with two imposing towers on its western side and a spacious cruciform choir. The church held a dual role as the royal chapel and a key player in political affairs, with its provost concurrently serving as Norway's Chancellor since 1314. Unfortunately, in 1523, the church fell victim to a fire sparked by the Swedish War of Independence against the Kalmar Union. Post the Protestant Reformation, its condition deteriorated to the point where restoration was infeasible, leading to its demolition in 1542.

Archaeological excavations commenced in 1867, led by Nicolay Nicolaysen under the supervision of Gerhard Fischer. Further excavations took place during the 1960s, led by Håkon Christie. Among the findings were remnants of an older wooden structure that Håkon Christie dated back to approximately 1050. Amidst the church ruins, the remains of two individuals were discovered and identified as King Haakon V and his Queen consort Euphemia of Rügen. These remains were subsequently re-interred in the Royal Mausoleum located within Akershus Castle.

Interestingly, the territory now occupied by the Norwegian Crown Prince Residence of Skaugum in the Asker municipality originally formed a part of the Saint Mary's Church's domain.