It was the king Sigurd Magnusson the Crusader who, in the first half of the 12th century, began the construction of Oslo's first cathedral. On the outskirts of what was then a small medieval town by the shoreline, a magnificent church building was established in honor of Oslo's patron saint, Hallvard.
For almost five hundred years, St. Hallvard's Cathedral served as the bishop's seat and the most important church of the capital. These were tumultuous years in the country's and the city's history, with Oslo being besieged, plundered, and burned countless times. In 1624, King Christian IV ordered the city to be moved westward so that it could be protected by the fortress at Akershus. Hallvard's Cathedral gradually fell into decay, until only the foundation below ground level remained, while a new cathedral was erected in the new Christiania.
In 1639, Oslo's second cathedral, Holy Trinity Church, was inaugurated. The church was centrally located at the highest point in the new city, by the market square, today known as Christiania Square, with the cathedral school and the town hall as its nearest neighbors.
If Hallvard's Cathedral is the cathedral that almost disappeared, Holy Trinity is the cathedral that completely vanished. Less than fifty years after it was completed, the beautiful church burned down. Instead of rebuilding it, it was decided to move Oslo's cathedral for the second time, likely for strategic reasons. The proximity to Akershus Fortress had proven problematic, among other things because the church tower obstructed the cannons on the fortress walls.
When the third cathedral was to be built, a site well outside the city was chosen, in the marshy and undeveloped area near the main gate into Christiania. The city looked quite different than it does today; the sea level was higher, and the church was built on a small hill outside the city walls which ran along what is now Karl Johans Gate.
The city's third cathedral was inaugurated on All Saints' Day in 1697. The church was constructed during a time of financial scarcity and externally had quite a spartan appearance, without significant decorations. The church was built of Dutch bricks painted with yellow and red stripes, as many of the city's buildings were. The tower was significantly lower then than now and did not have a spire.