Canute was born into the Danish royal family and became king of Denmark at the age of about 20. He soon set about conquering England, which had been ruled by the Anglo-Saxon king Æthelred the Unready since 978. Canute's invasion was initially successful, and he was crowned King of England in 1016. However, Æthelred's son, Edmund Ironside, led a rebellion against Canute and the two men eventually agreed to divide England between them. Canute ruled Wessex, while Edmund ruled Mercia.
Edmund died in 1017, leaving Canute as the sole ruler of England. He quickly established a strong and effective government and was popular with his English subjects. He also married Emma of Normandy, the widow of Æthelred the Unready, which helped to unite the English and Danish royal families.
In 1028, Canute invaded Norway and quickly defeated the Norwegian king, Olaf II. He was then crowned King of Norway and began to rule both England and Norway in a personal union. Canute also launched several military campaigns against Sweden and was successful in gaining control of parts of the country.
Canute was a successful and powerful ruler who managed to unite several different countries under his rule. He was also a generous patron of the arts and learning and was responsible for the construction of several churches and monasteries. He died in 1035 and was succeeded by his son, Harthacnut.