In 1028, Cnut sailed with 50 ships to Norway. Olaf was unprepared and "outgunned" because Cnut had prepared his way by bribing many of the Norwegian nobles for their support. 12th-century historian John of Worcester (previously mentioned here) says Cnut learned that Norwegian nobles were not content with Olaf's reign, so he sent them gold and silver to gain their loyalty.
Part of Cnut's plan relied on Haakon Ericsson, one-time governor of Norway until he was pushed out by Olaf, in the same Battle of Nesjar that made Olaf King of Norway. Hakon fled to England and was befriended by Cnut; Haakon's mother was said to be a sister of Svein Forkbeard, making the two men cousins. Cnut made him Earl of Worcester.
Cnut's army with the support of the Norwegian nobles very handily took over Norway. Olaf was driven to exile in the Kievan Rus. Cnut was declared King of Norway, and Haakon Ericsson was made his lieutenant there, managing Norway in Cnut's absence (which was frequent). (Unfortunately, Haakon died in a shipwreck in late 1029 or early 1030, between the Orkneys and the Scottish mainland.)
Olaf saw Haakon's absence as a reason to return to Norway with an army, including some Swedes. It did not go well for him: at the Battle of Stiklestad in 1030, his own people killed him.
Cnut now left Norway in the hands of his first wife, Ælfgifu of Northampton and Cnut's son by her, Svein Knutsson. This era experienced heavy taxation and a rebellion that led to the return of Olaf's dynasty.
You know, it's been almost an entire week about Cnut, and yet Olaf keeps weaving in and out of the story. I think it's time to look at Olaf, his bad decisions, how he became a saint, and how his illegitimate son eventually became king of Norway. We'll start that journey next time.
