Kjartan is a short form of Mýrkjartan, which is an Old Norse (Iceland) form of the Celtic name Muircheartach
First element (Muir-):
Old Irish muir = 'sea'
Last element (-cheartach):
Old Irish cheartach = 'warrior'
Kjartan is sometimes associated with the Irish name Certán as well.
VOYAGE OF GUDLEIF GUDLAUGSON TO GREAT IRELAND.A. D. 1029.
EYRBYGGJA SAGA, CAP. 64. VELLUM FRAGMENT, No. 4456, in 4to.
Bolti icelandic name
Kingdoms of Cnut
Hardicanute, the son of Canute and Emma of Normandy, was born in 1018. He inherited Denmark on his father's death in 1035, but was unable to come to England immediately to claim the throne. The Witan elected his half-brother, Harold Knutsson, as king instead.
Hardicanute organised an invasion of England but before he arrived, Harold died. He imposed a savage fleet-tax and this made him extremely unpopular with the English people. Hardicanute died in June 1042 after a drinking party
Harthacnut (Cnut the Hardy, sometimes Harthacanute, Hardicanute, Hardecanute,
Hörthaknútr; Danish: Hardeknud) (1018 – 8 June 1042) was King of Denmark from 1035 to 1042 as well as King of England from 1040 to 1042. He came from Northmannia according to Adam of Bremen and was the only son of Cnut the Great and Emma of Normandy.
He succeeded to the throne of Denmark in 1035, reigning as Cnut III, yet a war against Magnus I of Norway meant he could not secure his claim to the throne of England. Consequently, it was agreed that his elder illegitimate half-brother Harold Harefoot was to be regent there.
Harold took the English crown for himself in 1037 — Harthacnut being "forsaken because he was too long in Denmark"— and the Queen-mother, Emma, who had previously been resident at Winchester with some of her son's housecarls, was made to flee to Bruges, in Flanders. Harthacnut settled his difficulties in Scandinavia through a treaty he had made with Magnus in 1038 or 1039. This stated that they agreed that if one of them were to die without an heir the other should be his successor. Harthacnut then began to prepare for an invasion of England, and the deposition of Harold from the kingship. Harold, however, died on 17 March 1040, before any conquest could occur. Harthacnut was then invited to England, and the landing at Sandwich on 17 June 1040, "seven days before Midsummer", with a fleet of 62 warships was a peaceful one. He did though, with apparent scorn, command Harold's body to be taken from its tomb and cast in a fen with the animals.
Harthacnut was a harsh and unpopular ruler: to pay for his fleet, he severely increased the rate of taxation, and in 1041 the people of Worcester killed two of Harthacnut's housecarls who had been collecting the tax, prompting an attack by Harthacnut in which the city was burned. The story of Lady Godiva riding naked through the streets of Coventry to persuade the local earl to lower taxes may come from the reign of Harthacnut. The Anglo-Saxon Chronicle gives a dismal assessment of him: "He never accomplished anything kingly for as long as he ruled." It also says that in 1041 Harthacnut broke a pledge and betrayed Earl Eadwulf of Northumbria, who was under his safe conduct.
In 1041, Harthacnut invited his half-brother Edward the Confessor (his mother Emma's son by Ethelred the Unready) back from exile in Normandy to become a member of his household, and probably made Edward his heir. Harthacnut was unmarried and had no known children. It is rumoured he fathered an illegitimate son, William Canute. On 8 June 1042, he died at Lambeth — he "died as he stood at his drink, and he suddenly fell to the earth with an awful convulsion; and those who were close by took hold of him, and he spoke no word afterwards…" He was buried at Winchester, his father's place of rest, and his mother's, on her death. Edward assumed the throne on Harthacnut's death, restoring the Saxon royal line of Wessex