He put a definitive end to the civil war era when he had Skule Bårdsson killed in 1240, a year after he had himself proclaimed king in opposition to Haakon.

In conjunction with this he employed an active and aggressive foreign policy, and at the end of his rule added Iceland and the Norse Greenland community to his kingdom, leaving the Norwegian realm at its territorial height.

Commissioned by his son Magnus, it was written by the Icelandic writer and politician Sturla Þórðarson (nephew of the famous historian Snorri Sturluson).

He was dead by the time his son Haakon was born (many believed to have been poisoned by his Swedish stepmother Margaret), but Inga's claim was supported by several of the king's followers.

As the party was struck by a blizzard, two of the best Birkebeiner skiers, Torstein Skevla and Skjervald Skrukka, carried on with the child over the mountain from Lillehammer to Østerdalen.

[2][6] Haakon's dramatic childhood was often parallelled with that of former king Olaf Tryggvasson (who introduced Christianity to Norway),[7] as well as with the gospels and Child Jesus, which served an important ideological function for his kingship.

From the late civil war era, the government administration relied increasingly on written communication, which in turn demanded literate leaders.

[5] While Skule's supporters initially had attempted to cast doubt about Haakon's royal ancestry, they eventually suspended open resistance to his candidacy.

[16] In 1223 a great meeting of bishops, clergy, secular nobles, and other high-ranking figures from all across the country was held in Bergen to decide finally on Haakon's right to the throne.

However, The great meeting in Bergen soon after renewed the division of the Norwegian kingdom, with Skule gaining control of the northern third of the country instead of the east, in what marked a setback despite his military victory.

[18] As part of the campaign, Haakon additionally led a large army into the Värmland district of Sweden in 1225, to punish the inhabitants for their support of Sigurd.

[21] Periodically, the two nonetheless reconciled and spent a great amount of time together, only to have their friendship destroyed - according to the saga, by intrigues derived from rumours and slander by men who played the two against each other.

When a group of Karelians ("Bjarmians") had been forced westwards by the Mongols, Haakon allowed them to stay in the area surrounding the Malangen fjord and had them Christianized—something that would please the papacy.

The first work that was translated into Old Norse was reportedly the Arthurian romantic story Tristan and Iseult, which was finished in 1226 after orders from the young and newly-wed Haakon.

The influence of the reforms is also apparent in Haakon's Konungs skuggsjá ("King's Mirror"), an educational text intended for his son Magnus, which was probably written in cooperation with the royal court in the mid-1250s.

[33] In the north-east, the relationship with Novgorod had been tense due to a dispute over the right to tax the Sami people, as well as raiding from both Norwegian and Karelian sides.

Eventually, the Mongol invasion of Rus' drove Prince Alexander Nevsky to negotiations with Haakon that likely strengthened Norwegian control of Troms and Finnmark.

[26] In any case, Haakon's policy regarding Northern German ports largely derived from his strategy of attempting to exploit the internal turmoil in Denmark after the death of King Valdemar II in 1241.

In 1249, Haakon allied with Earl Birger for a joint Swedish-Norwegian invasion into Halland and Scania, but the agreement was eventually abandoned by the Swedes (see Treaty of Lödöse).

Haakon claimed Halland in 1253, and finally invaded the province on his own in 1256, demanding it as compensation for the looting of Norwegian ships in Danish seas.

Alfonso in turn sought to expand his influence in Northern Europe, as well as to gain Norwegian naval assistance for the campaign or crusade he had proposed in Morocco[37][38] (seeing that the Iberian Moors received backing overseas from North Africa).

[6] Further, the Norse community in Greenland agreed to submit to the Norwegian crown in 1261, and in 1262 Haakon achieved one of his long-standing ambitions when he incorporated Iceland into his kingdom by exploiting the island's internal conflicts in his favour.

The dependency on Norwegian maritime trade and their subordination to the Nidaros ecclesiastical province were some of the key reasons which allowed Haakon to assert sovereignty over the islands.

[6] Norwegian control over the Faroe Islands and Shetland was strong due to the importance of Bergen as a trading centre, while Orkney, the Hebrides, and Man had more natural ties with the Scottish mainland.

Although traditionally having had ties with the community of Norse settlers in northern Scotland, Scottish rulers had increasingly asserted their sovereignty over the entire mainland.

[46] As part of a new development the Scottish king Alexander II claimed the Hebrides and asked to buy the islands from Norway, but Haakon staunchly rejected the proposals.

[6] Centuries later, in 1531, the cathedral was demolished by the commander of Bergenhus, Eske Bille, for military purposes[55][56] in connection with the Protestant Reformation, and the graves of Haakon and other Norwegian kings buried there might have been destroyed in the process or moved to another location.

[58] Since the 1960s, historians including Narve Bjørgo, Per Sveaas Andersen, Knut Helle, Svein Haga, and Kåre Lunden have in turn professed a reaction against Koht's view.

[58] In his article in Norsk biografisk leksikon, Knut Helle acknowledges that Haakon was empowered by the strong institutional position of the kingship at the end of his reign (which he had developed himself), and that his policies were not always successful.

Helle nonetheless recognises the substantial political abilities and powerful determination Haakon must have had in order to progress from the difficult position in which he started his reign.