In 1217 Håkon IV became king of Norway, ushering in its Golden Age. During his long reign he modernised the Norwegian administration, brought Greenland, Iceland and parts of the British Isles into union with Norway and entered into lucrative trading agreements throughout the region.

Also during this period, the political centre of gravity of the kingdom moved from the south-west to the districts surrounding the Oslo Fjord, where a new capital was established. Håkon’s reign was also a period of considerable artistic flowering, during which the sagas were written.

However, Norway’s limited economic and military resources ultimately proved insufficient to maintain the empire which Håkon IV had created. By the early years of the 14th century the German Hanseatic towns (such as Bergen) had taken over the import-export trade, and the bubonic plague, which arrived in 1349 and subsequently wiped out two-thirds of the Norwegian population, further contributed to economic decline.

Meanwhile a shared fear of increased German power and influence prompted moves towards closer political ties between the three Scandinavian kingdoms. Following the death of King Håkon V (1270-1319), the Norwegian crown passed to Magnus Ericsson (1319-1374), son of Norwegian Princess Ingebjørg and Swedish Duke Eric. Magnus was subsequently elected king of Sweden, thus bringing about a union between the two kingdoms.

When his younger son Håkon came of age in 1355, Magnus placed him on the Norwegian throne; Håkon VI (1355-1380) later married Margrete, daughter of King Valdemar Atterdag of Denmark, and their son, Olav, was chosen to be Danish king on the death of Valdemar in 1375. Olav inherited the throne of Norway after his father’s death in 1380, thus bringing Norway into a union with Denmark which was to last until 1814. The culmination of these dynastic ties between Norway, Denmark and Sweden came in 1397 with the crowning of Margrete’s great-nephew Eric of Pomerania as king of the Kalmar union.