Harthacnut, the son of King Cnut and his second wife, Emma, held the English throne from the death of his half-brother, Harald Harefoot, in 1040 and until his own sudden death in 1042.
Harthacnut's birth must be placed within a few years of his parents' marriage in 1017, and he is first referred to, as a child accompanying his mother, in the Anglo-Saxon Chronicle's record of the translation of the relics of St Ælfheah from London to Canterbury in 1023.
After 1026 he began his political career as a figurehead for his father's authority in Denmark, and it seems likely that as he grew older he began to exert power there as his father's deputy. The problems associated with maintaining control of this region, in particular …
Bolton, Timothy. "Reign of King Harthacnut". The Literary Encyclopedia. First published 05 May 2006
[http://www.litencyc.com/php/stopics.php?rec=true&UID=1666, accessed 30 March 2017.]