Question: Who was the half-brother of Sweyn Haakonsson that participated in the conquest of English by King Canute the Great?
Context: St. Canute's Cathedral (Danish: Odense Domkirke or Sankt Knuds Kirke ), also known as Odense Cathedral, is named after the Danish king Canute the Saint (Danish: "Knud den Hellige" ), otherwise Canute IV.  It is a fine example of Brick Gothic architecture.  The church's most visited section is the crypt where the remains of Canute and his brother Benedict are on display. Cnut the Great (Old Norse: "Knútr inn ríki"; c. 995 – 12 November 1035), also known as Canute - whose father was Sweyn Forkbeard (which gave him the patronym "Sweynsson", Old Norse: "Sveinsson") - was King of Denmark, England and Norway; together often referred to as the North Sea Empire.  With the deaths of his heirs within a decade of his own, and Norman conquest of England in 1066, this legacy was mostly forgotten.  He is popularly invoked in the context of the legend of "King Canute and the waves", which usually misrepresents him as a deluded monarch believing he has supernatural powers, contrary to the original legend which portrays a wise king who rebuked his courtiers for their fawning behaviour. St. Alban's Church (Danish: "Sankt Albani Kirke" ) is the Roman Catholic parish church of Odense, Denmark.  It should not be confused with the medieval church of St. Alban's Priory where King Canute IV was murdered in 1086, and which was later replaced with St. Canute's Cathedral.  The medieval St. Alban's Priory was located at Albani Torv ("St. Alban's Square") roughly halfway between St. Canute's Cathedral and St. Alban's Church.  A modern stone plaque located at the site of the former church's altar is the only visible remain of this structure. Canute II the Tall (Swedish: "Knut Långe till Sko; Knut Holmgersson" ), was King of Sweden from 1229 until his death in 1234.  His father Holmger was called a "nepos" of King Canute I of Sweden, which usually meant "nephew".  It can thus be assumed that Canute II was a grandnephew of King Canute I.  He would then have been a great-grandson of King Eric the Saint; legends give Philip Ericson, King Eric's youngest son, as the father of Holmger, Canute's father.  Canute was closely allied with Folkungs, who wanted to limit the powers of the church and king. The story of King Canute and the waves is an apocryphal anecdote illustrating the piety or humility of King Canute the Great, recorded in the 12th century by Henry of Huntingdon. Ælfred Æþeling (English: "Alfred the Noble") (  1005 – died 1036) was one of the eight sons of the English king Æthelred the Unready.  He and his brother Edward the Confessor were sons of Ethelred's second wife Emma of Normandy.  King Canute became their stepfather when he married Aethelred's widow.  Alfred and his brother were caught in the power struggles at the start and end of Canute's reign. Boleslaw (Swedish: "Burislev"; died 1172/73) was a Swedish pretender for the throne, belonging to the House of Sverker.  He acted in concert with his kinsman Kol against King Canute I of Sweden, then head of the House of Eric.  The two pretenders, who were brothers, half-brothers, or uncle and nephew, may never have controlled much more than the Province of Östergötland, which was the base of the dynasty.  Boleslaw is believed either to have been murdered by King Canute's men, or to have fled to Poland in or before 1173. Henry was an 11th-century bishop and Christian missionary.  He was probably the keeper of the treasury of King Canute the Great in England.  Sometime before the year 1035, according to Adam of Bremen, Henry went to Orkney as bishop.  As Bishop of Orkney, he was probably more of a missionary bishop, and may have been under the metropolitan authority of the Archbishop of York.  He is possibly the Henry who went to Iceland for two undatable years.  In 1060/1, the King of Denmark, Sweyn II, appointed him Bishop of Lund.  He is the first man known to have held the bishopric of Lund, as well as Orkney.  He is said to have died from an alcoholic episode sometime in the mid-1060s. Sweyn Haakonsson (Old Norse: "Sveinn Hákonarson", Norwegian: "Svein Håkonsson" ) (died c. 1016) was an earl of the house of Hlaðir and co-ruler of Norway from 1000 to c. 1015.  He was the son of earl Hákon Sigurðarson.  He is first mentioned in connection with the battle of Hjörungavágr, where the "Heimskringla" says he commanded 60 ships.  After the battle of Svolder in the year 1000, Sveinn became co-ruler of Norway with his half-brother, Eiríkr Hákonarson.  After Eiríkr went to England in 1014, Sveinn was co-ruler with Hákon Eiríksson.  In 1015, Óláfr Haraldsson arrived in Norway and claimed the throne.  He defeated Sveinn and his allies in the battle of Nesjar.  Sveinn retreated to Sweden, intending to muster a force to retake Norway but he died of an illness before he could return. Eric Haakonsson (960s – 1020s) was Earl of Lade, Governor of Norway and Earl of Northumbria.  He was the son of Earl Hákon Sigurðarson and brother of the legendary Aud Haakonsdottir of Lade.  He participated in the Battle of Hjörungavágr, the Battle of Svolder and the conquest of England by King Canute the Great.
Answer: Eiríkr Hákonarson