Trondheim
Trondheim, historically Kaupangen, Nidaros, and Trondhjem, is a city and municipality in Trøndelag county, Norway. As of 2025, it had a population of 216,518. Trondheim is the third most populous municipality in Norway, and is the fourth largest urban area. Trondheim lies on the south shore of Trondheim Fjord at the mouth of the River Nidelva. Among the significant technology-oriented institutions headquartered in Trondheim are the Norwegian University of Science and Technology, the Foundation for Scientific and Industrial Research, the Geological Survey of Norway, and St. Olavs University Hospital.
The settlement was founded in 997 as a trading post and served as the capital of Norway through the Viking Age until 1217. From 1152 to 1537, the city was the seat of the Catholic Archdiocese of Nidaros; it then became, and has remained, the seat of the Lutheran Diocese of Nidaros and the site of the Nidaros Cathedral. The city was incorporated in 1838. The current municipality was formed in 1964, when Trondheim merged with Byneset Municipality, Leinstrand Municipality, Strinda Municipality, and Tiller Municipality, and further expanded on 1 January 2020, when Trondheim merged with Klæbu Municipality.
Trondheim has a mild climate for its northerly latitude, resulting in moderate summers and winters that often remain above the freezing point in seaside areas. At higher elevations, though, the microclimate is colder and snowier.
The city functions as the seat of the County Mayor of Trøndelag county but not as its administrative centre. This is designed to avoid making the county administration too centralized.
Trondheim is home to football club Rosenborg, Norway's most successful football club, and Granåsen Ski Centre, which has hosted the World Championship in Nordic Skiing.
Names and etymology
The city was established in 997 by Olav Tryggvason and it was originally named Nidaros. The first element of the name was the local river Nid. The last element of the name was which meant "the mouth of a river". Thus the name meant "the outlet of the river Nid". Although the formal name was Nidaros, the city was commonly known as, which means "city" or "marketplace", or more specifically kaupangr í Þróndheimi which means "the city in Trondheim". Trondheim was the historic name for the whole district which is now known as Trøndelag. This is the area where the people were known as Trønder. This district name Trondheim meant "the home of the Trønder people" and Trøndelag originally meant the "law area of the Trønder people". The name of the Trønder people derives from the Old Norse word which is an old present participle of the verb which means "to grow" or "to thrive".During the late Middle Ages, the city name was commonly shortened to Þróndheimr, dropping the kaupanger part, and over time the name became Trondhjem, using the Dano-Norwegian spelling rather than the Old Norse spelling since the city was part of the Kingdom of Denmark-Norway for centuries.
On 21 December 1917, a royal resolution enacted the 1917 Norwegian language reforms. Around the time, many municipalities and cities had their names changed to "Norwegianize" the spelling and make them look less Danish. On 1 January 1919, the name of the local Church of Norway diocese was changed from Trondhjem stift to Nidaros bispedømme. In 1924, the name of the Norwegian capital city was changed from Kristiania to Oslo, removing the name referencing a Danish King in favor of the very old name Oslo. In 1928, a referendum in Trondhjem was held on whether to keep the current name or to bring back the original name of Nidaros. The vote resulted in 17,163 votes in favour of Trondhjem and only 1,508 votes in favour of Nidaros. Despite this result, the Storting voted in 1929 to make some changes. The Trondhjem Cathedral would be changed to Nidaros Cathedral effective on 1 July 1929 and the name of the city would change to Nidaros starting on 1 January 1930. This change caused public outrage and even riots during 1930. This forced the Storting to reconsider this change. On 6 March 1931, the name was formally changed to Trondheim, using the medieval Norwegian spelling instead of the Danish version Trondhjem. The name of the diocese and cathedral, however, continued using the name Nidaros.
Trondheim was briefly named Drontheim during the Second World War as a German exonym.
History
Trondheim was named Kaupangen by Viking King Olav Tryggvason in 997 CE. Shortly after that, it came to be called Nidaros. Initially, it was frequently used as a military retainer of King Olav I. It was also frequently used as the king's seat and was Norway's capital until 1217.People have lived in the area for thousands of years, as evidenced by the rock carvings in central Norway, the Nøstvet and Lihult cultures, and the Corded Ware culture. In ancient times, the kings of Norway were hailed in Trondheim at Øretinget, the place for the assembly of all free men by the mouth of the River Nidelva. Harald Fairhair was hailed as the king here, as was his son, Haakon I, called 'the Good.' The battle of Kalvskinnet took place in Trondheim in 1179: King Sverre Sigurdsson and his Birkebeiner warriors were victorious against Erling Skakke. Some scholars believe that the famous Lewis chessmen, 12th-century chess pieces carved from walrus ivory that were found in the Hebrides and are now at the British Museum, may have been made in Trondheim.
From 1152, Trondheim was the seat of the Archbishop of Nidaros for Norway, which operated from the Archbishop's Palace. Due to the introduction of Lutheran Protestantism in 1537, the last archbishop, Olav Engelbrektsson, had to flee from the city to the Netherlands; he died in what today is Lier, Belgium.
From the 16th through the 19th centuries, the city was repeatedly ravaged by fires that caused widespread damage since many of its buildings were made of wood. The worst occurred in 1598, 1651, 1681, 1708, 1717, 1742, 1788, 1841 and 1842. The 1651 fire destroyed 90% of all buildings within the city limits. After the "Horneman Fire" in 1681, there was an almost total reconstruction of the city, overseen by General Johan Caspar von Cicignon, originally from Luxembourg. Broad avenues, such as Munkegata, were created, without regard for private property rights, to limit the damage from future fires. At the time, the city had a population of under 10,000 inhabitants, with most living in the downtown area.
After the Treaty of Roskilde on 26 February 1658, Trondheim and the rest of Trøndelag became Swedish territory briefly. However, after a three-month long siege, the area was reconquered 10 months later. The conflict was finally settled by the Treaty of Copenhagen on 27 May 1660.
During the Second World War, Trondheim was occupied by Nazi Germany from 9 April 1940, the first day of the invasion of Norway, until the end of the war in Europe, 8 May 1945. The German invasion force consisted of the German cruiser Admiral Hipper, 4 destroyers and 1700 Austrian Mountain troops. Except for a coastal battery that opened fire, there was no resistance to the invasion, which began on 9 April at 5 AM. On 14 and 17 April, British and French forces landed near Trondheim in a failed attempt to liberate Trondheim, as part of the Namsos Campaign. During the occupation, Trondheim was the home of the notorious Norwegian Gestapo agent, Henry Rinnan, who operated from a nearby villa and infiltrated Norwegian resistance groups. The city and its citizens were subjected to harsh treatment by the occupying power, including the imposition of martial law in October 1942. During this time, the Germans turned the city and its environs into a major base for submarines, and contemplated a scheme to build a new city for 300,000 inhabitants, Nordstern, centred southwest of Trondheim, near the wetlands of Øysand on the outskirts of Melhus municipality. This new metropolis was to be accompanied by a massively expanded version of the already existing naval base, which was intended to become the future primary stronghold of the German Kriegsmarine. A start was made on this enormous construction project, but it was far from completed when the war ended, and today, there are few physical remains of it.