A couple of praise poems by his court poet Þorbjörn Hornklofi survive in fragments, but the extant accounts of his life come from sagas set down in writing around three centuries after his lifetime.

Though the king's sagas and medieval accounts have been critically scrutinised during the twentieth and early twenty-first centuries, Harald maintains a reputation as the father of the Norwegian nation.

However, Peter Sawyer began to cast doubt on this in 1976,[12] and the decades around 2000 saw a wave of revisionist research that suggested that Harald Fairhair did not exist, or at least not in a way resembling his appearance in sagas.

[30] Krag has noted that Snorri's account of Harald's origin in Vestfold might have been propaganda as the area of Viken was disputed between the Norwegian and Danish crown in the thirteenth century.

Krag points of that Othere describes Viken as Danish territory and Hrafnsmál's description of the battle of Hafrsfjord suggest that Harald was attacked by "eastern" enemies that were routed and fled back east.

Hrafnsmál largely consists of a conversation between an unnamed valkyrie and a raven; the two discuss the life and martial deeds of Harald Fairhair.

Sendibitr, the last and shortest poem Snorri quotes is attributed to Jórunn skáldmær (Jorunn the skaldmaiden), one of few female poets mentioned in the sagas.

Iceland was settled by "malcontents" from Norway, who resented Harald's claim of rights of taxation over lands, which the possessors appear to have previously held in absolute ownership.

The text describes Halfdan the Black's death by going through the ice on Randsfjorden, a story also told by Snorri in Heimskringla, and that Harald became king afterwards.

Historia Norwegiæ, which is dated to about 1220, mentions that Iceland was discovered in the time of Harald Fairhair by Ingólfr Arnarson and Hjörleifr Hróðmarsson.

The work describes the history of the Yngling-dynasty from the legendary king Ingvi as Harald's ancestors and Halfdan the Black was his father.

Harald Fairhair is said to have inherited Halfdan's lands at a young age after the king drowned in the lake Rǫnd in Rykinsvik.

Harald was therefore induced to take a vow not to cut nor comb his hair until he was "þjóðkonungr" (people-king) of Norway, and when he was justified in trimming it ten years later, he exchanged the epithet "Shockhead" or "Tanglehair" (Haraldr lúfa) for the one by which he is usually known.

[35][c][36] In 866, Harald made the first of a series of conquests over the many petty kingdoms which would compose all of Norway,[35] including Värmland in Sweden, which had sworn allegiance to the Swedish saga-king Erik Eymundsson (whose historicity is not confirmed).

Harald established the royal estate of Hlade in Trondheim and Håkon became the first of the Earls of Lade, a family which would be one of the dominating forces in Norway for the next 150 years.

At last, Harald was forced to make an expedition to the West, to clear the islands and the Scottish mainland of some Vikings who tried to hide there.

Harald is said to have divorced Åsa and rejected Gyda and several other concubines to marry a Jutish princess called Ragnhild the Mighty.

Harald drove Erik Eymundsson out of Värmland and inserted Áki's son Ubbi (Swedish: Ubbe) as jarl.

Snæfrith's sons Halfdan Long-Leg and Gudrød Ljome burned Rognvald jarl alive in his hall and took his lands in More and Orkney.

The estates in Møre are returned to Rognvald's other son Thorir the Silent who was given Harald's daughter Ålov in marriage as compensation.

This accounts differs from Heimskringla where it is said that Harald made a marriage alliance with Håkon Grjotgardsson which won him Trøndelag after they together defeated the petty kings there.

The saga then related how Harald did battle with the combined forces of kings Audbjörn of Firðafylki, Solvi Bandy-legs of Møre og Romsdal and Arnvid of Sunnmøre.

Gretti's great-grandfather Önundr Wood-foot is said to be one of many people that fled Norway after fighting for king Kjotvi the Rich and Thorir Haklang in the battle of Hafrsfjord.

The saga describes how Harald and his elite Úlfhèðnar warriors (famously mentioned in Hrafnsmál) fought and killed Thorir Haklang when he went berserk.

Önundr got his name after his leg was crushed beneath the knee by the prow of one of the king's ships and he had to walk on a wooden pegleg for the rest of his life.

The marriage of Sigurd Snake-in-the-Eye and Blaeja could not have occurred earlier than 867, which would put the dating Harald's ascension to kingship of Norway in 872 into question.

Fagrskinna makes no mention of Blaeja and states that Ragnhild Sigurdsdotter was Sigurd Snake-in-the-Eye's daughter and not his great-granddaughter, which seems more plausible in regards to the dating of events.

Once, historians could write that no-one denied the reality of Harald Fairhair's expeditions to the west (recounted in detail in the Heimskringla), but this is no longer the case.

Thomson (2008) writes that Harald's "great voyage is so thoroughly ingrained in popular and scholarly history, both ancient and modern, that it comes as a bit of a shock to realise that it might not be true.

He gave them all the royal title and assigned lands to them, which they were to govern as his representatives; but this arrangement did not put an end to the discord, which continued into the next reign.