It all started back in Harthacnut’s day. In 1040, the soon-to-be King of England and Magnus I of Norway made a treaty that if one of them died childless, the other would inherit his kingdom (sounds a lot like Canute and Edmund Ironside). When Harthacnut died childless, the Witan decided to elect Edward the Confessor instead, and Magnus threatened to invade and assert his claim. Apparently the English didn’t take the threat too seriously, though Edward is said to have accused his mother Emma of favoring Magnus’s cause. He retaliated by relieving her of Canute’s treasure. Nonetheless, Magnus’s successor, Harald Sigurdsson (Hardrada) must have inherited the treaty as well as the throne, and hence he had a claim to the English crown…not that he needed much of an excuse.
So when King Edward died, Duke William wasn’t Harold Godwineson’s only rival. But by all indications, Hardrada’s invasion plans weren’t taken seriously. Or did Harold know about them at all? One of our titillating questions about 1066 is: when did Hardrada make his plans, and did the vengeful Tostig have anything to do with it?
As the popular story goes, Tostig first went to Sweyn Estridsson’s court in Denmark and tried to talk his cousin into invading England. After all, the Danish King was the grandson of Sweyn Forkbeard, so he was in line to the throne of England. But after 15 hard years of conflict with Harald Hardrada, Sweyn was exhausted and so was his treasury. Disappointed, Tostig went on to Norway and gave Harald such a pep talk that the formidable king was chomping at the proverbial bit. According to Snorri Sturleson in HEIMSKRINGLA, Tostig assured Harald “If you wish to gain possession of England, then I may bring it about that most of the chieftains in England will be on your side and support you.” He added: “All men know that no greater warrior has arisen in the North than you; and it seems strange to me that you have fought fifteen years to gain possession of Denmark and don’t want to have England which is yours for the having.” What self-respecting Norseman could resist that line of reasoning?
Snorri has this conversation take place in the winter, which gave Hardrada the spring and summer to raise his army. However, not all historians agree with this scenario. The venerable Edward A. Freeman concluded that there wasn’t enough time for Tostig to make the voyage AND for Hardrada to raise an army. He concluded that Hardrada had planned the campaign on his own and Tostig joined up with him after he made his move. It has also been suggested that Tostig sent Copsig, his right-hand man in his old earldom, as an ambassador to Norway to plan the invasion and didn’t meet Harald in person until later.
Whether Tostig went to Norway in 1066 or not, historians agree that he spent the summer at King Malcolm’s court in Scotland and joined up with Hardrada after Harald dropped off his queen in the Orkneys and came south with the Orkney Earls. Some think Harald stopped at Dunfermline where Malcolm and Tostig waited. William of Malmesbury thought that Tostig joined Hardrada and pledged his support when the Norwegians reached the Humber, which is very late in the story. Regardless, by that point Harald Sigurdsson was clearly in charge of the expedition, and Tostig was his subordinate.