England breaks away from Danish control in 1035 and Denmark falls into disarray for some time.

Sweyn Estridsen's son, Canute IV, raids England for the last time in 1085.

He plans another invasion to take the throne of England from an aging William I.

He calls up a fleet of one thousand Danish ships, sixty Norwegian long boats, with plans to meet with another six hundred ships under Count Robert of Flanders in the summer of 1086.

Canute, however, is beginning to realize that the imposition of the tithe on Danish peasants and nobles to fund the expansion of monasteries and churches and a new head tax (Danish: nefgjald) has brought his people to the verge of rebellion.

Canute takes weeks to arrive at Struer where the fleet has assembled, but he finds only the Norwegians still there.

Canute's nephew Sweyn Estridson (1020–74) re-establishes strong royal Danish authority and builds a good relationship with Archbishop Adalbert of Hamburg-Bremen—at this time the Archbishop of all of Scandinavia.

Northwest Europe (964 – 1107 CE): Norman Conquest, Insular Kingdoms, and North Sea Networks

Geographic and Environmental Context

Northwest Europe includes Iceland, Ireland, the United Kingdom, the Faroe, Shetland, and Orkney Islands, the Channel Islands, and the western coastal zones of Norway and Denmark (west of 10°E).

• Anchors: London–York–Winchester, Dublin–Waterford–Cork, Bergen–Trondheim, Orkney–Shetland–Faroe–Iceland, Channel ports (Southampton, Dover).

Climate and Environmental Shifts

• Warm conditions supported population growth; herring shoals and cod grounds underpinned fisheries from North Sea to Iceland.

Societies and Political Developments

• England: consolidation under Anglo-Saxon kings (Æthelred II, Cnut the Great, 1016–1035, Edward the Confessor).

• Norman Conquest (1066): William seized England; castles, feudal estates, Domesday Book (1086).

• Ireland: Norse towns remained semi-autonomous; Irish high-kings (Brian Boru, d. 1014 at Clontarf).

• Scotland: Kings Malcolm II–III consolidated Lowlands; Norse jarls remained strong in Orkney/Hebrides.

• Norway/Denmark: Cnut’s North Sea Empire (England–Denmark–Norway); later Norway consolidated under Olaf Haraldsson (St. Olaf, d. 1030).

• Iceland: Christianization (c. 1000), Althing maintained self-rule under Norwegian overlordship by late 11th c.

Economy and Trade

• London grew as a major European port.

• Dublin, York thrived on slave trade, silver, and hides.

• North Sea commerce: wool, cloth, salt, fish; Norwegian timber and iron traded south.

• Flemish cloth towns (Ghent, Bruges, just across boundary in Atlantic West Europe) were key markets for English wool.

Belief and Symbolism

• Christianization of Scandinavia; churches founded across Norway, Denmark, and Iceland.

• Monastic expansion in England, Ireland, Scotland; Norman Romanesque architecture flourished.

Long-Term Significance

By 1107, the Norman monarchy dominated England; Scandinavia and Iceland were Christianized; the North Sea was a connected political and economic system.

Harold Godwinson becomes king, in all likelihood appointed by Edward the Confessor on his deathbed and endorsed by the Witan.

William of Normandy, Harald Hardråde (aided by Harold Godwin's estranged brother Tostig) and Sweyn II of Denmark all assert claims to the throne.

By far the strongest hereditary claim is that of Edgar the Ætheling, but his youth and apparent lack of powerful supporters cause him to be passed over, and he does not play a major part in the struggles of 1066, though he is made king for a short time by the Witan after the death of Harold Godwinson.

King Cnut of England and Denmark seeks to restore Danish rights in Norway, lost in 1016 upon the ascension of native Olaf Haraldsson as monarch.

Olaf and King Anund Jacob of Sweden, seeing the combined Anglo-Danish kingdom as a threat—Cnut's father Sweyn had asserted power over both their countries—take advantage of Cnut's being in England to attack the Danes in the Baltic Sea in 1025 or 1026, and are joined by Ulf Jarl, Cnut's Danish regent, and his brother.

Ulf Jarl is the son of Thorgils Sprakalägg, who is claimed to have been the son of Styrbjörn the Strong, a scion of the Swedish royal house, by Tyra, the daughter of king Harald Bluetooth of Denmark.

However, Thorgils' parentage may have been invented to glorify the royal dynasty founded by Ulf's son, Sweyn Estridson.

Ulf had joined Cnut’s expedition to England.

He had married Cnut's sister Estrid in about 1015 and was appointed the Jarl of Denmark, which he rules when Cnut is absent.

He is also the foster-father of Cnut's son Harthacnut.

When the Swedish and Norwegian kings attack Denmark, Ulf persuades the freemen, who are discontent at Cnut's absentee rule, to elect Harthacnut king.

This is a ruse on Ulf's part, as his role as Harthacnut's guardian will make him the ruler of Denmark.

When Cnut learns what has happened, he returns to Denmark and confronts his enemies at the Battle of the Helgeå, where the Swedish and the Norwegian navies led by kings Anund Jacob and Olaf II lie in wait up a river for the navy of King Cnut, which is commanded by Ulf Jarl.

Cnut's navy is massive and his own ship is said to have been eighty meters long.

The Swedish and the Norwegian kings had ordered a large dam made of peat and lumber to built on the river.

When the Danish navy sails in, the water is released and a great many Danes and Englishmen drown in the deluge.

However, Cnut's men are apparently able to win the battle.

The outcome is disputed, but Cnut comes out best; Olaf flees and the threat to Denmark is dispelled.

The apparent victory leaves Cnut as the dominant leader in Scandinavia.

The battle is retold in skaldic poetry and in sources such as the Danish Gesta Danorum by Saxo Grammaticus and the Icelandic Saga of Olaf the Holy by Snorri Sturluson.

Opinions are divided on whether the location was at Helgeå in Uppland or the Helgeå of eastern Skåne.

In the Anglo-Saxon Chronicle, the battle is dated to 1025 and the Swedes won the battle.

Cnut claims to rule "part of Sweden" together with England, Denmark, and Norway.

At some time after the Battle of the Helgeå, he subjugates the core provinces of Sweden around Lake Mälaren, where he has his own coins minted either in the capital, Sigtuna, or in Lund, at this time part of Denmark, with the inscription CNVT REX SW ("Cnut King of the Swedes").

Western Götaland or Blekinge have been suggested.

It is probably an overlordship more than actual rule; Cnut does not have to be present in Sweden to order the minting of coins.

Coins are also minted asserting he rules Ireland, and Swedish history at this early date is so uncertain that we can hardly be sure even of the names of the kings.

Ulf's assistance to Cnut at the Battle of the Helgeå has not caused Cnut to forgive Ulf for his coup.

At a banquet in Roskilde, the two brothers-in-law are playing chess and start arguing with each other.

The next day, Christmas of 1026, Cnut has one of his housecarls kill Earl Ulf in Trinity Church, the predecessor of Roskilde Cathedral.

Accounts are contradictory, however.

Ulf is the father of Sweyn Estridson, and thus the progenitor of the House of Estridsen, which will rule Denmark from 1047 to 1375, and which is also sometimes, specially in Swedish sources, referred to as the Ulfinger dynasty to honor him.

Einar Thambarskelfir and Kalf Arnesson, after receiving the approval of Ingegerd, return from Novgorod with Magnus to Sigtuna in early 1035, and receive backing from the Swedish king, brother of Magnus's stepmother Astrid.

Astrid immediately becomes an important supporter of Magnus, and an army is gathered in Sweden, headed by Einar and Kalf, to place Magnus on the Norwegian throne.

Nako, having turned to Christianity after his defeat in the Battle of Recknitz in 955, had established his seat at Mecklenburg.

His sons Mstivoj and Mstidrag and grandsons Mstislaw and Udo are mostly associated with the Slavic uprising of 983.

All of them had either abandoned Christianity or were "bad Christians" (at least for a time).

Udo was a bad Christian (male christianus according to Adam of Bremen) whose own father, Mistiwoi, had renounced the new religion for the old Slavic paganism.

Udo had sent his son to be educated at the monastery of St. Michael at Lenzen and later at Lüneburg.

After a Saxon murdered Udo in 1028, Gottschalk had renounced Christianity and assumed the leadership of the Liutici to avenge his father, killing many Saxons before Duke Bernard II of Saxony defeated and captured him; his lands had gone to Ratibor of the Polabians.

Reconverted to Christianity, Gottschalk had been released and sent to Denmark with many of his people to serve King Cnut in his wars with Norway.

Sveyn Estridson, Jarl of Denmark, desired independence from King Magnus I of Norway in 1042.

Because Magnus is supported by his brother-in-law, Bernard II, Sveyn achieves an alliance with the Obotrites through the mediation of Gottschalk.

However, the Obotrite chief Ratibor is killed in a siege by Magnus in 1043.

In an attempt to avenge their father, his sons are killed in the same year in a battle at Lürschau Heath on 28 September.

The death of Ratibor and his sons allows Gottschalk, who marries Sveyn's daughter Sigrid, to seek the inheritance of his father Udo as Prince of the Obodrites.

The celebrated Norse warrior Harald Hardrada, the half brother of Norway’s King Olaf II, for whom he had fought at the Battle of Stiklestad, had initially served as a mercenary under Yaroslav, grand duke of Kiev, whose daughter Elisiv he has married.

It is possible that the marriage with Elisiv had been agreed to already during Harald's first time in Rus', or that they at least had been acquainted.

During his service in the elite Varangian Guard of Emperor Michael IV in Constantinople, Harald had composed a love poem which included the verse "Yet the goddess in Russia/ will not accept my gold rings" (whom Snorri Sturluson identifies with Elisiv), although Morkinskinna claims that Harald had to remind Yaroslav of the promised marriage when he returned to Kiev.

According to the same source, Harald had spoken with Yaroslav during his first time in Rus', requesting to marry Elisiv, only to be rejected because he was not yet wealthy enough.

It is in any case significant that Harald had been allowed to marry the daughter of Yaroslav, since his other children are married to figures such as Henry I of France, Andrew I of Hungary and the daughter of Constantine IX.

Seeking to regain for himself the kingdom lost by his half-brother Olaf Haraldsson, Harald had begun his journey westwards in early 1045, departing from Novgorod (Holmgard) to Staraya Ladoga (Aldeigjuborg) where he obtained a ship.

His journey had gone through Lake Ladoga, down the Neva River, and then into the Gulf of Finland and the Baltic Sea.

He arrives in Sigtuna in Sweden, probably at the end of 1045 or in early 1046.

When he arrives in Sweden, according to the skald Tjodolv Arnorsson, his ship is unbalanced by its heavy load of gold.

In Harald's absence, the throne of Norway had been restored to Magnus the Good, an illegitimate son of Olaf.

Harald may actually have known this, and it could have been the reason why Harald wanted to return to Norway in the first place.

Since Cnut the Great's sons had chosen to abandon Norway and instead fight over England, and his sons and successors Harold Harefoot and Harthacnut had died young, Magnus's position as king had been secured.

No domestic threats or insurrections are recorded to have occurred during his eleven-year reign.

After the death of Harthacnut, which had left the Danish throne vacant, Magnus had in addition been selected to be the king of Denmark, and had managed to defeat the Danish royal pretender Sweyn Estridsson.

Harald, having heard of Sweyn's defeat by Magnus, meets up with his fellow exile in Sweden (who is also his nephew), as well as with the Swedish king Anund Jacob, and the three join forces against Magnus.

Their first military exploit consists of raiding the Danish coast, in an effort to impress the natives by demonstrating that Magnus offers them no protection, and thus leading them to submit to Harald and Sweyn.

Magnus, learning of their actions, knows that Norway will be their next target.