Harald Fairhair joined earls and small kings to gather Norway into one kingdom, among them were Håkon Grjotgardsson Earl-Lade and Ragnvald Earl-Møre. The Battle of Hafsfjord was in 872 and he reigned from 865 to 930-933. But it didn´t take long before Norway again became a suzerainty under Denmark. Håkon Sigurdsson Earl ruled Norway as sub-king of the Danish King from 970, first under Harald Blåtann, then under Svein Tjugeskjegg. But he was too independent and autonomous, so the Danish king sent a great fleet northwards along the coast to punish him. But Håkon was warned and gathered a fleet of vikingships, with the help of “leidangen” and won over them at the Battle of Hjørungavåg in Sunnmøre, likely about 986.
Denmark tried to win over both Norway and England. Norwegian Vikings traveled like vikings as well, but Olav Tryggvasson received the Christian faith in England, then tried to gather Norway in one kingdom again. Olav Haraldson den Heilage received the Christian faith in Normandy and then he also tried to gather Norway into one kingdom. In both cases the Danish king was trying to take power in England. But after he managed to take back the power in Norway.
It was the people in Trøndelag who won in the battle of Stiklestad but the Danish collected the fruit of it. King Knut set his son Svein on the throne in Norway, even though he was just a child, with his Anglo-Saxon mother Alfiva as his guardian. Now Knut could reign directly through them, instead of through the Norwegian earls like earlier. The Norwegian petty kings didn´t like this, especially Einar Tambarskjelve in Trøndelag. The tribe of Earl Lade had died out on the man-side, so he had hoped to become the new Earl Lade. And now the Danisthey introduced new law, taxes and heavy burdens on the people. In addition there came famine in Europe, so this was a hard time.
Church leaders claimed Olav Haraldson to be a saint because of some reported miracles. Einar Tambarskjelve and other great men made an alliance with the Church leaders and picked up Olav´s son, Magnus, in Gardariket, to make him the king of Norway, so Svein and Alfiva had to escape.
Thus, Noreg lasted the same way, and it is important to understand the unequivocal significance of Christianity. Noreg was cooperating with Christianity because it had been shown that kyrkja had an important co-operation and social function. Noreg was a samla under Christianity, because Christ is king of kings, so faith in his work as a samlande supranationality.
Now Norway became independent and autonomous and I think it is important to understand what Christianity meant for this. Norway was gathered with Christianity because it had been shown that the Church had an important gathering and social function. Norway was gathered under Christianity, because Christ is king of kings, so faith in him functions as a gathering super-nationality.
The viking-time starts about 800 bf.Ch.
The viking-time is said to start with the attack at the monestry in Lindisfarne i 793, even though it was an attack on defenseless people and was not much to be proud of, compared to the tough Viking journeys.
It was a peaceless time, in which the strongest prevailed. A small king could easily be temted to attack a neighboring king’s territory with fire and sword. A common farmer could not feel safe, a stranger might suddenly challenge him to the “holmgang” to try to take from him farm and house or his daughter. At Sunnmøre there was a Swedish lineage and named Ljot the Pale, he had no friends in the village but gained goods and gold through “holmgang”. He claimed a daughter at Blindheim (near Ålesund) in that way, but Egil fought him and felled him. (Cappelens Norgeshistorie 1976, volume 2 page 63).
“Holmgang” means to be put ashore on a small island (“holme”), two men were left there until only one of them was alive.
Harald Fairhair and the unification of Norway.
Harald Fairhair was a king who wanted to propose to a young woman named Gyda and was dotter of a king in Hordaland. But she didn’t want to come to him until he’d joined Norway to the realm. So he said he wouldn’t cut hair and beard until he’d gathered Norway into one kingdom. Then he first tried to make small kings and earls join him voluntarily support as Norway’s king. Many agree that he was from Sogn on the west-coast, north of Hordaland.
Ynglingætta was a royal tribe in Vestfold and Oppland, but neither he nor his father, Halvdan Svart, is a tribunal in Ynglingetal. Remarkebly little ties him to Vestfold. (Cappelens Norgeshistorie 1976, volume 2 page 88) Perhaps he came from a more northern branch of the ynglinge-tribe, but most truly he was king on Ringerike and Hadeland and then took Vestfold as well. The most radical theory is that he was from Rogalands and that it was primarily the people of vestfold he won over in the Battle of Hafsfjord.
Norway means the road to the north, it was the sea route along the coast and there was a trade route. To ensure it could have been a good reason to gather Norway to one kingdom. Kaupang in Vestfold was a trading town on the coast, where it was handed with great values, so they needed a king for protection. Harald Fairhair was supported by Lade Earl Ragnvald Møre Earl. Lade was a loading point in Trondheimsfjorden and the people further north were interested in safeing the trade route along the coast. To the south Møre is the coastline in Møre og Romsdal.
On this site https://en.wikipedia.org/wiki/Unification_of_Norway we find maps of Norway from 820 until 1020 and I qoote:
King Harald Fairhair is the monarch who is credited by later tradition as having first unified Norway into one kingdom. According to the sagas, he ruled Norway from approximately 872 to 930. Modern historians, including Claus Krag, assume that his rule may have been limited to the coastal areas of western and southern Norway. The tendency in recent research has been to perceive unification of the nation to have been a more time-consuming process.
The sagas recount that Harald succeeded, on the death of his father Halfdan the Black Gudrödarson, to the sovereignty of several small, and somewhat scattered kingdoms in Vestfold, which had come into his father’s hands through conquest and inheritance. In 866, Harald made the first of a series of conquests over the many petty kingdoms which would compose Norway, including Värmland in Sweden, and modern day south-eastern Norway, which had sworn allegiance to the Swedish king Erik Eymundsson. In 872, after a great victory at the Battle of Hafrsfjord near Stavanger, Harald found himself king over the whole country.
According to Sverre Bagge, unification of Norway was made easy by excellent sea communications, as well as seas that rarely froze in winter.
His realm was, however, threatened by dangers from outside, as large numbers of his opponents had taken refuge, not only in Iceland, then recently discovered; but also in the Orkney Islands, Shetland Islands, Hebrides Islands and Faroe Islands. His opponents’ leaving was not entirely voluntary. Many Norwegian chieftains who were wealthy and respected posed a threat to Harald; therefore, they were subjected to much harassment, prompting them to vacate the land. In time, Harald was forced to make an expedition to subdue these islands.
After Harald’s death, the unity of the kingdom was not preserved. In following centuries, the kingdom was variously ruled, wholly or in part, by descendants of King Harald or by earls under the suzerainty of Denmark. Kings of Norway until King Olav IV, who died in 1387, commonly claimed descent from Harald Fairhair.
In the Saga of Harald Hårfagre from Heimskringla by Snorri Sturluson, the consolidation of the rule of Norway by Harald Fairhair was somewhat of a love story. The tale begins with a marriage proposal that resulted in rejection and scorn from Gyda, the daughter of Eirik, king of Hordaland. She said she refused to marry Harald “before he was king over all of Norway”. Harald was therefore induced to take a vow not to cut nor comb his hair until he was sole king of Norway, and that ten years later, he was justified in trimming it; whereupon he exchanged the epithet “Shockhead” or “Tanglehair” for the one by which he is usually known. Most scholars today regard this story as a literary tale inspired by the Romance stories that were popular at the courts by the time Heimskringla was written.
I quote from https://en.wikipedia.org/wiki/Rognvald_Eysteinsson :
It is not certain that the Ragnall of the Irish annals is synonymous with Rognvald Eysteinsson. The relevant entry goes on to describe Ragnall’s older sons raiding in Spain and North Africa, but there is no specific mention of the Earldom of Orkney. There is also a separate piece of circumstantial evidence, suggesting a link between Ragnall and the 9th century figure Ragnar Lodbrok: runic inscriptions found inside Maeshowe, dating from the 12th century, state that the mound was “built before Loðbrók”.
There is no agreement in the available sources on Rognvald’s parentage. According to the Irish annals, Ragnall was the son of “Halfdan, King of Lochlann“. This is generally understood to mean Halfdan the Black, which would make Ragnall the brother of King Harald Fairhair. This is contradicted by later Norse sagas, which suggest that Halfdan was Rognvald’s grandfather. The Orkneyinga saga says that Rognvald was the son of Eystein Ivarsson and grandson of Ívarr Upplendingajarl.
Both sagas refer to six sons. The oldest, “by concubines”, were Hallad, Einarr and Hrollaug, who were “grown men when their brothers born in marriage were still children”. The latter were Ivar, Hrólfr, and Thorir the Silent. Hrólfr, who “was so big that no horse could carry him”, hence his byname of “Ganger-Hrólf”, (which means “by foot”) is identified by the saga writers with Rollo, founder of the Duchy of Normandy (in 911).
In the Orkneyinga saga Rognvald was made the Earl of Møre by Harald Fairhair. The Saga of Harald Fairhair in Heimskringla recounts that Rognvald caused Harald Fairhair to be given his byname by cutting and dressing his hair, which had been uncut for ten years on account of his vow never to cut it until he was ruler of all Norway. Rognvald accompanied the king on a great military expedition. First the islands of Shetland and Orkney were cleared of Vikings who had been raiding Norway and then continued on to Scotland, Ireland and the Isle of Man. During this campaign Rognvald’s son Ivarr was killed and in compensation Harald granted Rognvald Orkney and Shetland.
Rognvald thereafter returned to Norway, giving the northern isles to his brother Sigurd Eysteinsson. Sigurd had been the forecastleman on Harald’s ship and after sailing back east the king “gave Sigurd the title of earl”.
In Ålesund there is a statue of Gange-Rolv “Rollon”. He moved to Normandy and was a relatively great king there.
Battle of Hjørungavåg.
Harald Fairhair joined earls and small kings to gather Norway into one kingdom, among them were Håkon Grjotgardsson Lade-earl and Ragnvald Møre-earl. The Battle of Hafsfjord was in 872 and he reigned from 865 to 930-933. But it didn´t take long before Norway again became a suzerainty under Denmark. Håkon Sigurdsson Earl ruled Norway as sub-king of the Danish King from 970, first under Harald Blåtann, then under Svein Tjugeskjegg. But he was too independent and autonomous, so the Danish king sent a great fleet northwards along the coast to punish him. But Håkon was warned and gathered a fleet of vikingships, with the help of “leidangen” and won over them at the Battle of Hjørungavåg in Sunnmøre, likely about 986.
During this period, Denmark was the dominant power in the Nordic region. Southern Norway and the Oslo Fjord sometimes lay directly under Danish rule. Haakon Sigurdsson ruled Norway as a vassal of King Harald Bluetooth of Denmark (died c. 985/86), but for the most part seemed to remain an independent ruler. Haakon was a strong believer in the old Norse gods. When Harald Bluetooth attempted to force Christianity upon him around 975, Haakon broke his allegiance to Denmark. Harald Bluetooth had suffered defeat from Otto II, Holy Roman Emperor during 974. Haakon took advantage of the weakened position of the Danish king to make Norway independent of Denmark. With the convincing victory, Haakon Sigurdsson remained Norway’s sole ruler and Denmark’s claim over Norway was rejected and not repeated again until the Battle of Svolder about fourteen years later.  
Jómsvíkinga saga offers two mutually contradictory descriptions of the bay on the coast of Sunnmøre in which the battle took place. According to the first one, Hjorungavágr lies on the landward side of the island Hoð (now Hareidlandet in Møre og Romsdal). According to the other, the bay is situated south of an island called Primsigð/Primsignd and north of an island called Horund. Both of these names are not in common use today.   
The battle is described in the Norse kings’ sagas—including Heimskringla—as well as in Jómsvíkinga saga and Saxo Grammaticus‘ Gesta Danorum. Saxo Grammaticus estimated that the battle took place while Harald Bluetooth was still alive. Tradition has set the battle in 986. Some contemporary skaldic poetry alludes to the battle, including verses by Þórðr Kolbeinsson and Tindr Hallkelsson. The battle was also the subject of later poems and sagas. Jómsvíkingadrápa by Bjarni Kolbeinsson honors the fallen Jomsvikings at the Battle of Hjörungavágr. Vellekla, composed by the Icelandic skald Einarr Helgason, speaks of the Battle of Hjörungavágr. Fagrskinna, contains a history of Norway with a heavy emphasis on battles, including the Battle of Hjörungavágr.
When Harald Fairhair was old, there was a dispute between his sons, the eldest of them, Eirik, wanted the whole kingdom gathered, so he got war against some of them and killed five of them. Therefore he was called Eirik Bloodaxe. But his brother, Håkon, came home from England and Eirik had to escape from the country. Håkon was called Haakon the Good.
Harald 2. Graycloak was the son of Eirik Blodøks and he won over Håkon the Good and took power. He killed the father of Olav Tryggvason before he was born, so his mother, Astrid, fled from the land, maybe to Orkney or Sweden, but the written histories agree that Astrid eventually came to Gardariket (Kiev), since her brother was in service at Vladimir the Great of Kiev, so Olav was raised there.
Keisar Otto 2nd of the German-Roman Empire made an army expedition to the Nordic countries and joined Olav Tryggvasson in the team. Dei met the armies of the Danish king Harald Blåtann and Håkon Jarl of Norway. At first they did not manage to break through, but then they sailed around Jutland and won a great battle, so king, earl and army men were made Christians. But later, Håkon returnd to the old religion.
Olav Tryggvason still raided like Vikings, but as he raided England he repented to Christianity. Then he sailed back to Norway and wanted to unify the people and the country into one kingdom with Christianity and under Christianity. So it was in agreement with the English king, but against the Danish king, even though he also had repented to Christianity. This was while the Danish king tried to take England, but later the Danish king fought against Olav Tryggvason and won at the battle of Svolder.
This is a simplification, her it is told much more about it, https://en.wikipedia.org/wiki/Olaf_Tryggvason :
Olaf Tryggvason (960s – 9 September 1000) was King of Norway from 995 to 1000. He was the son of Tryggvi Olafsson, king of Viken (Vingulmark, and Rånrike), and, according to later sagas, the great-grandson of Harald Fairhair, first King of Norway. He is numbered as Olaf I.
Olaf is seen as an important factor in the conversion of the Norse to Christianity. He is said to have built the first Christian church in Norway, in 995, and to have founded the city of Trondheim in 997. A statue of Olaf Tryggvason is located in the city’s central plaza.
Historical information on Olaf is sparse. He is mentioned in some contemporary English sources, and some skaldic poems. The oldest narrative source mentioning him briefly is Adam of Bremen‘s Gesta Hammaburgensis ecclesiae pontificum of circa 1070.
In the 1190s, two Latin versions of “Óláfs saga Tryggvasonar“ were written in Iceland, by Oddr Snorrason and by Gunnlaugr Leifsson – these are now lost, but are thought to form the basis of later Norse versions. Snorri Sturluson gives an extensive account of Olaf in the Heimskringla saga of circa 1230, using Oddr Snorrason’s saga as his primary source. Modern historians do not assume that these late sources are accurate, and their credibility is debated. The most detailed account is named Óláfs saga Tryggvasonar en mesta (“Greatest Saga of Óláfr Tryggvason”) and is recorded in the Flateyjarbók, and in the early 15th-century Bergsbók.
Birth and early life.
There is uncertainty of both the date and the place of Olaf’s birth. The earliest Norwegian written source, the Historia Norwegiæ of the late twelfth century, states that Olaf was born in the Orkney Islands after his mother fled there to escape the killers of Olaf’s father. Another late 12th-century source, Ágrip af Nóregskonungasögum, states that Olaf’s mother fled to Orkney with Olaf when he was three years old for the same reason. All the sagas agree that Olaf eventually came to Kievan Rus’, specifically the court of Vladimir the Great of Kiev.
The version in Heimskringla is the most elaborate, but also the latest, and introduces elements to the story that are not found in earlier sources. It states that Olaf was born shortly after the murder of his father in 963, while other sources suggest a date between 964 and 969. The later dates cast doubt over Olaf’s claim to be of Harald Fairhair’s kin, and the legitimacy of his claim to the throne. Snorri Sturluson claims in Olaf Tryggvson’s saga that Olaf was born on an islet in Fjærlandsvatnet, where his mother Astrid Eiriksdottir, daughter of Eirik Bjodaskalle, was hiding from her husband’s killers, led by Harald Greycloak, the son of Eirik Bloodaxe. Greycloak and his brothers had seized the throne from Haakon the Good. Astrid fled to her father’s home in Oppland, then went on to Sweden where she thought she and Olaf would be safe. Greycloak sent emissaries to the king of Sweden, and asked for permission to take the boy back to Norway, where he would be raised by Greycloak’s mother Gunhild. The Swedish king gave them men to help them claim the young boy, but to no avail. After a short scuffle Astrid (with her son) fled again. This time their destination was Gardarike (Kiev), where Astrid’s brother Sigurd was in the service of Vladimir the Great. Olaf was three years old when they set sail on a merchant ship for Novgorod. The journey was not successful: in the Baltic Sea they were captured by Estonian vikings, and the people aboard were either killed or taken as slaves. Olaf became the possession of a man named Klerkon, together with his foster father Thorolf and his son Thorgils. Klerkon considered Thorolf too old to be useful as a slave and killed him, and then sold the two boys to a man named Klerk for a ram. Olaf was then sold to a man called Reas for a fine cloak. Six years later, Sigurd Eirikson traveled to Estonia to collect taxes for King Vladimir. He saw a boy who did not appear to be a native. He asked the boy about his family, and the boy told him he was Olaf, son of Tryggve Olafson and Astrid Eiriksdattir. Sigurd then went to Reas and bought Olaf and Thorgils out from slavery, and took the boys with him to Novgorod to live under the protection of Vladimir.
Still according to Heimskringla, one day in the Novgorod marketplace Olaf encountered Klerkon, his enslaver and the murderer of his foster father. Olaf killed Klerkon with an axe blow to the head. A mob followed the young boy as he fled to his protector Queen Allogia, with the intent of killing him for his misdeed. Only after Allogia had paid blood money for Olaf did the mob calm down. As Olaf grew older, Vladimir made him chief over his men-at-arms, but after a couple years the king became wary of Olaf and his popularity with his soldiers. Fearing he might be a threat to the safety of his reign, Vladimir stopped treating Olaf as a friend. Olaf decided that it was better for him to seek his fortune elsewhere, and set out for the Baltic.
Heimskringla states that after leaving Novgorod, Olaf raided settlements and ports with success. In 982 he was caught in a storm and made port in Wendland, where he met Queen Geira, a daughter of King Burizleif. She ruled the part of Wendland in which Olaf had landed, and Olaf and his men were given an offer to stay for the winter. Olaf accepted and after courting the Queen, they were married. Olaf began to reclaim the baronies which while under Geira’s rule had refused to pay taxes. After these successful campaigns, he began raiding again both in Skåne and Gotland.
Relationship and marriage to Geira.
Olaf Tryggvason’s relationship with Geira began when Geira was warned that were a large number of ships sitting in the harbor outside of her kingdom. Queen Geira told the man who informed her to invite them to her kingdom, telling him that she would have them over for a feast. Once Olaf and his men arrived, Queen Geira welcomed them in, held a feast for them, and engaged in very meaningful conversation with Olaf. This conversation led to Olaf and his men staying for a few days, and a relationship starting between the two leaders. Eventually these two would agree to a marriage while Olaf and his troops were still there. Later, during one of their conversations, Olaf asked Geira if there were any towns that she had lost control over. She replied, “Lord, I can name for you the towns that have escaped from our control; we have suffered their arrogance for a long time.” Following this conversation, Olaf went out and recaptured these towns for Geira. Following this, and their marriage, Olaf would stay in the country until the untimely death of Geira.
Alliance with Emperor Otto II.
Holy Roman Emperor Otto II assembled a great army of Saxons, Franks, Frisians, and Wends to fight the Norse pagan Danes. Olaf was part of this army because his father-in-law was king of Wendland. Otto’s army met the armies of King Harald Bluetooth and Haakon Jarl, the ruler of Norway under the Danish king, at Danevirke, a great wall near Schleswig. Otto’s army was unable to break the fortification, so he changed tactics and sailed around it to Jutland with a large fleet. Otto won a large battle there, and forced Harald and Haakon with their armies to convert to Christianity. The constituents of Otto’s army then returned to their homelands. Harald held to his new religion, but Haakon returned to worshipping the pagan gods when he came home.
Death of Geira and conversion.
After Olaf had spent three years in Wendland, his wife Geira died. He felt so much sorrow from her death that he could no longer bear to stay in Wendland, and set out to plunder in 984. He raided from Friesland to the Hebrides. After four years he landed on one of the Scilly Isles. He heard of a seer who lived there. Desiring to test the seer, he sent one of his men to pose as Olaf. But the seer was not fooled. So Olaf went to see the hermit, now convinced he was a real fortune teller. And the seer told him:
Thou wilt become a renowned king, and do celebrated deeds. Many men wilt thou bring to faith and baptism, and both to thy own and others’ good; and that thou mayst have no doubt of the truth of this answer, listen to these tokens. When thou comest to thy ships many of thy people will conspire against thee, and then a battle will follow in which many of thy men will fall, and thou wilt be wounded almost to death, and carried upon a shield to thy ship; yet after seven days thou shalt be well of thy wounds, and immediately thou shalt let thyself be baptized.
After the meeting mutineers attacked Olaf, and he was wounded but survived, and as a result he converted to Christianity.
By another account, Saint Ælfheah of Canterbury baptised him near Andover, Hampshire, England in 994. However, Henrietta Leyser, the author of Ælfheah’s entry in the Oxford National Dictionary of Biography, states that Olaf was already baptised and that the 994 event at Andover was a confirmation of his faith, part of a Danegeld treaty in which he agreed to no longer raid in England.
Following the death of Geira, it states in The Saga of Olaf that he travelled to Russia. During his stay here, he had a dream in which God spoke to him. The voice he heard said, “Hear me, you who promise to be a good man, for you never worshipped gods or paid them any reverence. But rather you disgraced them, and for that reason your works will be multiplied for good and profitable ends. Still you are very deficient in those qualities that would allow you to be in these regions and make you deserving to live here in eternity, because you do not know your Creator and you do not know who the true God is.”
Marriage to Gyda.
In 988, Olaf sailed to England, because a thing had been called by Queen Gyda, sister of Olaf Cuaran, King of Dublin. Gyda was the widow of an earl, and was searching for a new husband. A great many men had come, but Gyda singled out Olaf, though he was wearing his bad weather clothes, and the other men wore their finest clothing. They were to be married, but another man, Alfvine, took objection, and challenged Olaf and his men to the Scandinavian duel or holmgang. Olaf and his men fought Alfvine’s crew and won every battle, but did not kill any of them; instead, they bound them. Alfvine was told to leave the country and never come back again. Gyda and Olaf married, and spent half their time in England and the other half in Ireland.
Ascent to the throne.
In 995, rumours began to surface in Norway of a king in Ireland of Norwegian blood. This caught the ear of Jarl Haakon, who sent Thorer Klakka to Ireland, posing as a merchant, to see if he was the son of Tryggve Olafson. Haakon told Thorer that if it were him, to lure him to Norway, so Haakon could have him under his power. Thorer befriended Olaf and told him of the situation in Norway, that Jarl Haakon had become unpopular with the populace, because he often took daughters of the elite as concubines, which was his right as ruler. He quickly grew tired of them and sent them home after a week or two. He had also been weakened by his fighting with the Danish king, due to his rejection of the Christian faith.
Olaf seized this opportunity, and sailed for Norway. When he arrived many men had already revolted against Haakon, who was forced to hide in a hole dug in a pigsty, together with his slave, Kark. When Olaf met the rebels they accepted him as their king, and together they started to search for Haakon. They eventually came to the farm where Haakon and Kark were hiding, but did not find them. Olaf held a meeting just outside the swine-sty and promised a great reward for the man who killed Haakon. The two men in the hole heard this speech, and Haakon became distrustful of Kark, fearing he would kill him for the reward. He could not leave the pigsty, nor could he stay awake indefinitely, and when he fell asleep Kark decapitated Haakon with a knife. The next day Kark went to Olaf and presented him the head of Haakon. King Olaf did not reward him, and instead decapitated him.
After his confirmation as King of Norway, Olaf traveled to the parts of Norway that had not been under the rule of Haakon, but that of the King of Denmark; they also swore allegiance to him. He then demanded that they all be baptised, and most reluctantly they agreed.
In 997, Olaf founded his seat of government in Trondheim, where he had first held a thing with the revolters against Haakon. It was a suitable site because the River Nid twisted itself before going into the fjord, creating a peninsula that could be easily defended against terrestrial attacks by only one short wall.
Olaf continued to promote Christianity throughout his reign. He baptized the explorer Leif Ericson, who took a priest with him back to Greenland to convert the rest of his kin. Olaf also converted the people and Earl of the Orkney Islands to Christianity. At that time, the Orkney Islands were part of Norway.
It has been suggested that Olaf’s ambition was to rule a united Christian Scandinavia, and it is known that he made overtures of marriage to Sigrid the Haughty, queen of Sweden, but negotiations failed because of her steadfast pagan faith. Instead, he made an enemy of her, and did not hesitate to involve himself in a quarrel with King Sweyn I of Denmark by marrying Sweyn’s sister Tyra, who had fled from her heathen husband Burislav, the semi-legendary “King of Wends“, in defiance of her brother’s authority.
Both his Wendish and his Irish wife had brought Olaf wealth and good fortune, but, according to the Sagas, his last wife, Tyra, was his undoing, for it was on an expedition undertaken in 1000 to wrest her lands from Burislav that he was waylaid off the island Svolder by the combined Swedish, Danish, and Wendish fleets, together with the ships of Earl Haakon’s sons. The Battle of Svolder ended in the death of the Norwegian king. Olaf fought to the last on his great vessel Ormrinn Langi (Long Serpent), the mightiest ship in the North, and finally leapt overboard and was seen no more.
In the early 11th century, a Viking chieftain named Tryggvi invaded Norway, claiming to be the son of Olaf and Gyda. His invasion was defeated by forces loyal to Cnut the Great‘s son Svein Knutsson. An account preserved in Morkinskinna relates that Tryggvi was killed by a farmer after the battle. Many years later, when Harald Hardrada was king of Norway, he passed by the site of the battle. The king met an old friend of his who pointed out the alleged assassin. After questioning the purported killer and hearing him confess, King Harald had the man hanged, citing the familial bond between him and Tryggvi and his duty to avenge the latter’s death.
For some time after the Battle of Svolder, there were rumors that Olaf had survived his leap into the sea and had made his way to safety. Accounts reported by Oddr Snorrason included sightings of Olaf in Rome, Jerusalem, and elsewhere in Europe and the Mediterranean. Both King Ethelred the Unready and Olaf’s sister Astrid allegedly received gifts from Olaf long after he was presumed dead. The latest sighting reported by Oddr took place in 1046.
Olaf routinely used force to compel conversion to Christianity, including execution and torture of those who refused. Raud the Strong refused to convert and, after a failed attempt using a wooden pin to pry open his mouth to insert a snake, was killed by a snake goaded by a hot poker through a drinking horn into Raud’s mouth and down his throat. Eyvind Kinnrifi likewise refused and was killed by a brazier of hot coals resting on his belly. The possibly apocryphal figure, Sigrid the Haughty was said to have refused to marry Olaf if it meant forgoing her forefathers’ religion, upon which Olaf slapped her with his glove, an act that prompted her to unite his enemies against him years later.
The kings paid «danegeld» to the Vikings to be left in peace. Both Olav Tryggvason and Olav Haraldson got danegeld. But as they repented to Christianity they changed “policy”.
I quote from https://en.wikipedia.org/wiki/Danegeld :
Danegeld (/ˈdeɪnɡɛld/; “Danish tax”, literally “Dane yield” or tribute) was a tax raised to pay tribute to the Viking raiders to save a land from being ravaged. It was called the geld or gafol in eleventh-century sources. It was characteristic of royal policy in both England and Francia during the ninth through eleventh centuries, collected both as tributary, to buy off the attackers, and as stipendiary, to pay the defensive forces. The term danegeld did not appear until the late eleventh century. In Anglo-Saxon England tribute payments to the Danes was known as gafol and the levy raised to support the standing army, for the defense of the realm, was known as heregeld (army-tax).
An English payment of 10,000 Roman pounds (3,300 kg) of silver was first made in 991 following the Viking victory at the Battle of Maldon in Essex, when Æthelred was advised by Sigeric the Serious, Archbishop of Canterbury, and the aldermen of the south-western provinces to buy off the Vikings rather than continue the armed struggle. One manuscript of the Anglo-Saxon Chronicle said Olav Tryggvason led the Viking forces.[a]
In 994 the Danes, under King Sweyn Forkbeard and Olav Tryggvason, returned and laid siege to London. They were once more bought off, and the amount of silver paid impressed the Danes with the idea that it was more profitable to extort payments from the English than to take whatever booty they could plunder.[a]
Further payments were made in 1002, and in 1007 Æthelred bought two years peace with the Danes for 36,000 troy pounds (13,400 kg) of silver. In 1012, following the capture and murder of the Archbishop of Canterbury, and the sack of Canterbury, the Danes were bought off with another 48,000 troy pounds (17,900 kg) of silver.[a]
In 1016 Sweyn Forkbeard’s son, Canute, became King of England. After two years he felt sufficiently in control of his new kingdom to the extent of being able to pay off all but 40 ships of his invasion fleet, which were retained as a personal bodyguard, with a huge Danegeld of 72,000 troy pounds (26,900 kg) of silver collected nationally, plus a further 10,500 pounds (3,900 kg) of silver collected from London.
This kind of extorted tribute was not unique to England: according to Snorri Sturluson and Rimbert, Finland, Estonia and Latvia (see also Grobin, now Grobiņa) paid the same kind of tribute to the Swedes. In fact, the Primary Chronicle relates that the regions paying protection money extended east towards Moscow, until the Finnic and Slavic tribes rebelled and drove the Varangians overseas. Similarly, the Sami peoples were frequently forced to pay tribute in the form of pelts. A similar procedure also existed in Iberia, where the contemporary Christian states were largely supported on tribute gold from the taifa kingdoms.[b]
It is estimated that the total amount of money paid by the Anglo-Saxons amounted to some sixty million pence. More Anglo-Saxon pennies of this period have been found in Sweden than in England, and at the farm where the runestone Sö 260 talks of a voyage in the West, a hoard of several hundred English coins was found.
St. Olav Haraldson.
Olav Haraldson was the son of Åsta and Harald Grenske, a small king in Vestfold. So his father was the great-great-grandson of Harald Fairhair, but he died before Olav was born. Olav went in Viking voyages to Finnland and the Baltic countries, Denmark and England. Torkjell Høge was a jomsviking and petty king in Skåne. Olav was with him in the attack on Canterburry in 1011.
https://en.wikipedia.org/wiki/Olaf_II_of_Norway Olav Haraldson raided like a Viking in England and along the coast of the mainland.
I quote from https://snl.no/Olav_den_hellige :
“In the autumn of 1009 Olav came to England as part of Torkell Høy’s army, and became involved in Svein Tjugeskjegg’s battle against King Ethelred on 2 May 1909. In 1010 Olav probably took part in a major battle at Ringmare in East Anglia, and later in the conquest and plundering of Canterbury. There Archbishop Ælfeah was captured to ransom for him, but he was later killed by his captors. King Ethelred 2 paid a large sum to prevent new attacks and for Torkell Høye to enter his ministry.
In 1012 Olav travelled to Normandy, where he was the tenement officer for Duke Richard 2. Here he participated in several battles, including a battle at Dol against the Duke of Brittany. During this period he is said to have travelled south towards the Iberian Peninsula, and according to the sagas, is said to have come all the way to Gibraltar before turning north again. Olav was probably accompanied by other Normans into the Mediterranean to Palestine and southern Italy, where they had been both mercenaries and pilgrims for several years.”
But in Normandie he repented of Christianity. Now the English King Ethelred 2 had escaped to Normandie, since the Danish king Svein Tjuveskjegg had gained the upper hand in England. But then Svein and died and Olav Haraldson was truly with Etherel 2 back to England, to help him regain power. Svein’s son, Knut, escaped and went home, but returned the following year, with a large fleet. Then Olav returned to Norway to gather it with Christianity as a Norwegian king on new.
He managed it, but again the Danish king managed to fight back and take over, so Olav fell at the Battle of Stiklestad.
Here we get to know much more about it https://en.wikipedia.org/wiki/Olaf_II_of_Norway :
Olaf II Haraldsson (c. 995 – 29 July 1030), later known as Saint Olaf (and traditionally as St. Olave), was King of Norway from 1015 to 1028. Son of Harald Grenske, a petty king in Vestfold, Norway, he was posthumously given the title Rex Perpetuus Norvegiae (English: Eternal/Perpetual King of Norway) and canonised at Nidaros (Trondheim) by Bishop Grimkell, one year after his death in the Battle of Stiklestad on 29 July 1030. His remains were enshrined in Nidaros Cathedral, built over his burial site. His sainthood encouraged the widespread adoption of Christianity by Scandinavia‘s Vikings/Norsemen.
Pope Alexander III confirmed Olaf’s local canonisation in 1164, making him a universally recognised saint of the Roman Catholic Church and started to be known as Rex Perpetuus Norvegiae – eternal king of Norway. He became an equally important saint of the Eastern Orthodox Church (feast day 29 July) and one of the last famous saints before the Great Schism. Following the Reformation he was a commemorated historical figure among some members of the Lutheran and Anglican Communions.
The saga of Olav Haraldsson and the legend of Olaf the Saint became central to a national identity. Especially during the period of romantic nationalism, Olaf was a symbol of Norwegian independence and pride. Saint Olaf is symbolised by the axe in Norway’s coat of arms and Olsok (29 July) is still his day of celebration. Many Christian institutions with Scandinavian links as well as Norway’s Order of St. Olav are named after him.
As a teenager Olaf went to the Baltic, then to Denmark and later to England. Skaldic poetry suggests he led a successful seaborne attack that took down London Bridge, though Anglo-Saxon sources do not confirm this. This may have been in 1014, restoring London and the English throne to Æthelred the Unready and removing Cnut. According to Snorri’s Heimskringla, the attack happened soon after the death of Sweyn Forkbeard with the city being held by Danish forces. Snorri’s account claims that Olaf assisted Æthelred in driving the Danes out of England. Olaf is also said by Snorri to have aided the sons of Æthelred after his death. Olaf is said to have won battles but been unable to assist Æthelred’s sons in driving Cnut out. After this, he set his sights on Norway.
Olaf saw it as his calling to unite Norway into one kingdom, as Harald Fairhair had largely succeeded in doing. On the way home he wintered with Duke Richard II of Normandy. Norsemen had conquered this region in 881. Richard was himself an ardent Christian, and the Normans had also previously converted to Christianity. Before leaving, Olaf was baptised in Rouen in the pre-Romanesque Notre-Dame Cathedral by Richard’s brother Robert the Dane, archbishop of Normandy.
Olaf returned to Norway in 1015 and declared himself king, obtaining the support of the five petty kings of the Norwegian Uplands. In 1016 at the Battle of Nesjar he defeated Earl Sweyn, one of the earls of Lade and hitherto the de facto ruler of Norway. He founded the town of Borg, later known as Sarpsborg, by the waterfall Sarpsfossen in Østfold county. Within a few years he had won more power than any of his predecessors on the throne had enjoyed.
Olaf annihilated the petty kings of the South, subdued the aristocracy, asserted his suzerainty in the Orkney Islands, and conducted a successful raid on Denmark. He made peace with King Olof Skötkonung of Sweden through Þorgnýr the Lawspeaker, and was for some time engaged to Olof’s daughter, Ingegerd, though without Olof’s approval. In 1019 Olaf married Astrid Olofsdotter, King Olof’s illegitimate daughter and the half-sister of his former fiancée. The union produced a daughter, Wulfhild, who married Ordulf, Duke of Saxony in 1042.
But Olaf’s success was short-lived. In 1026 he lost the Battle of the Helgeå, and in 1029 the Norwegian nobles, seething with discontent, supported the invasion of King Cnut the Great of Denmark. Olaf was driven into exile in Kievan Rus.  He stayed for some time in the Swedish province of Nerike, where, according to local legend, he baptised many locals. In 1029, King Cnut’s Norwegian regent, Jarl Håkon Eiriksson, was lost at sea and Olaf seized the opportunity to win back the kingdom. Given military and logistical support by the Swedish king Anund Jacob he tried to bypass the formidable “Øresundfleet” of the Danish king by traveling across the Jämtland-mountains to take Nidaros, the Norwegian capital at the time, in 1030. However, Olaf was killed in Battle of Stiklestad, where some of his own subjects from central and northern Norway took arms against him. The exact position of Saint Olaf’s grave in Nidaros has been unknown since 1568, due to the effects of the Lutheran iconoclasm in 1536–37.
King Cnut, though distracted by the task of governing England, ruled Norway for five years after Stiklestad, with his son Svein and Svein’s mother Ælfgifu (known as Álfífa in Old Norse sources) as regents. But their regency was unpopular, and when Olaf’s illegitimate son Magnus (‘the Good’) laid claim to the Norwegian throne, Svein and Ælfgifu were forced to flee.