The Trinity Church (Trefoldighetskirken) is one of the largest churches in Oslo (1000 seats). The church itself is in the raw red brick, while the vaults, arches and small columns have gray scale color. The nave is octagonal with a Greek cross superimposed, with the choir in the apse, shallow transept and rectangular entrance flanked by two slender, octagonal bell towers. A central dome rises above the church.
The Trinity Church was consecrated in 1858 by Bishop Jens Lauritz Arup. The church has a neo-Gothic central plant, with two towers and eight-sided dome, and was designed by architect Alexis de Chateauneuf (Hamburg, Germany), but some time after the work was entrusted to his pupil Wilhelm von Hanno, who made some modifications to the original plans and put his personal stamp on the details of interior decoration. The main body (1872) is the work of Claus Jensen, the altarpiece (1866) is a painting by Adolph Tidemand (the Baptism of Jesus), chandeliers were designed by Emanuel Vigeland in 1923, and Frøydis Haavardsholm was the designer of the stained glass windows.
References:Visby Cathedral (also known as St. Mary’s Church) is the only survived medieval church in Visby. It was originally built for German merchants and inaugurated in 1225. Around the year 1350 the church was enlarged and converted into a basilica. The two-storey magazine was also added then above the nave as a warehouse for merchants.
Following the Reformation, the church was transformed into a parish church for the town of Visby. All other churches were abandoned. Shortly after the Reformation, in 1572, Gotland was made into its own Diocese, and the church designated its cathedral.
There is not much left of the original interior. The font is made of local red marble in the 13th century. The pulpit was made in Lübeck in 1684. There are 400 graves under the church floor.