But though Canute spent most of his time in England, and valued his English possessions more than any other of his lands, he was during the greater part of his reign occupied in foreign wars with the object of building up a grand empire in northern Europe. It was in the first of these wars that Earl Godwin gained his confidence. In 1019, Canute having settled his power beyond all danger of a revolution, made a voyage to Denmark, in order to make a campaign against the King of Sweden; and he carried along with him a large body of the English, under the command of Earl Godwin. The Earl was stationed next the Swedish camp; and observing a favourable opportunity, which he was obliged suddenly to seize, he attacked the enemy in the night, drove them from their trenches, threw them into disorder, pursued his advantage, and obtained a decisive victory over them. Next morning, Canute, seeing the English camp abandoned, imagined that those disaffected troops had deserted to the enemy: he was agreeably surprised to find that they were at that time engaged in pursuit of the discomfited Swedes. He was so pleased with this success, and with the manner of obtaining it, that he bestowed his niece in marriage on Godwin, and treated him ever after with entire confidence and regard.
The wars with Sweden terminated in the submission of that kingdom to Canute as over-king, and in 1028 he attacked Norway, and drove the just, but unwarlike Olaf from the land. Canute was thus ruler over Denmark, Sweden, and Norway, and none of the English kings, either before or since his time, have ever been rulers over so large a portion of Europe.
It was not likely that so powerful a monarch would tolerate the existence of an independent kingdom to the north of England, and Malcolm of Scotland forced an issue by invading Northumberland at the beginning of the reign. In 1031, therefore, Canute found occasion to approach the Scottish frontier with a powerful army. The King of Scots had no choice but to submit, and acknowledge Canute as his lord, and his nephew, Duncan, did homage for Cumberland at the same time. Duncan is well known to us through Shakespeare's play, and it is remarkable that among the under-kings who did homage to Canute was a certain Mælboethe, who is doubtless identical with Macbeth.