Trondheim (trôn´hām), city (1995 pop. 142,792), capital of Sør-Trøndelag co., central Norway, a port on the Trondheimsfjord (an arm of the Atlantic Ocean). It is also known by its original name, Nidaros. The third largest city of Norway, it is a commercial, industrial, and shipping center. Manufactures include metal goods, construction materials, textiles, processed food, and forest products. Founded in 997 by Olaf I, the king who introduced Christianity to Norway, the city was the political and religious capital of medieval Norway. In 1152, Nicholas Breakspear (later Pope Adrian IV) made it a archiepiscopal see. The city was also an important trade center until the Hanseatic period, when its trade was largely diverted (14th cent.) to Bergen. Olaf Engelbrektsson, archbishop of Nidaros, strongly resisted (early 16th cent.) the attempt of King Christian III to force the Reformation on Norway and defended the rights of Norway as a separate kingdom. However, in 1537, Engelbrektsson was obliged to flee, and in the same year the Reformation was introduced and Roman Catholic bishoprics were abolished. Renamed Trondheim (or Trondhjem), the city declined considerably after this blow to its religious ascendancy. In 1681 it was severely damaged by a fire. Only in the mid-19th cent. did Trondheim reemerge as an important economic center. Its position was enhanced when Haakon VII was crowned (1906) in Nidaros Cathedral as the first king of modern, independent Norway; subsequent rulers of Norway have also been crowned there. In World War II, Trondheim was occupied by the Germans on the first day (Apr. 9, 1940) of their invasion of Norway. It became a major German naval base and as such was frequently bombed by the Allies. Today Trondheim is a well-planned city. Its celebrated cathedral, originally a church erected over the tomb of Olaf II (St. Olaf) in the 11th cent., was built in the 12th and 13th cent., but it was later ravaged by several fires. Reconstruction was begun in 1869, and the completed structure, built of Norwegian blue soapstone and white marble, is considered by many to be the finest Gothic-style cathedral in Scandinavia. Also of note in the city is the Stiftsgaard, a large wooden building (18th cent.) that serves as a royal residence.