Nidaros Cathedral is a Church of Norway cathedral located in the city of Trondheim in Sor-Trondelag county, Norway. It was the cathedral of the Roman Catholic Archdiocese of Nidaros from its establishment in 1152 until its abolition in 1537. Since the Reformation, it has been the cathedral of the Lutheran bishops of Trondheim (or Nidaros) in the Diocese of Nidaros. The architectural style of the cathedral is Romanesque and Gothic. Historically it was an important destination for pilgrims coming from all of Northern Europe. It is the northernmost medieval cathedral in the World.
Along with Var Frue Church, the cathedral is part of the Nidaros og Var Frue parish in the Nidaros deanery in the Diocese of Nidaros.
Work on the cathedral started in 1070 and was finished sometime around 1300. The cathedral was badly damaged by fires in 1327 and again in 1531. The nave west of the transept was destroyed and was not rebuilt until the restoration in early 1900s. In 1708 it burned down completely except for the stone walls. It was struck by lightning in 1719, and was again ravaged by fire. Major rebuilding and restoration of the cathedral started in 1869, initially led by architect Heinrich Ernst Schirmer, and nearly completed by Christian Christie. It was officially completed in 2001. Maintenance of the cathedral is an ongoing process.