Geira, the daughter of Busislav, played an important role in history: she died. Her death resulted in her husband, Olaf, King of Norway, becoming depressed and deciding to go on a raid. On this raid, he was converted to Christianity, and brought it back to Norway with him.
In this Alternative History, Geira does not die, and Olaf does not go on the raid. He stays a Norse Pagan, and does not attempt to convert the Norse People to Christianity. In fact, he does quite the opposite: he vents is sadistic torture/excecution methods on Christians, not Pagans.
Because this happens, Leif Erikson is not converted by Olaf. However, he does question Olaf about the religion that the King of Norway is persecuting so much against, and Olaf informs Leif more about it. Leif takes home this information to Greenland, and his mother decides that Christianity is right. She converts her son, and Leif decides to help Christians in Norway and the rest of Scandinavia escape to Greenland. This results in both larger Greenland Colonies, as well as the continuation of settlement in Vinland.
Meanwhile, Olaf I, instead of attacking England, decides that all the Pagan Nations should unite to stop Christianity, which he has begun to despise. The Finns were not strong and organized enough to resist him, so in order to protect their sovereignty, they vowed to send aid if Norway ever went to war with the Christians. The Swedes, on the other hand, did not want to become Norway's junior partner in the alliance. A war broke out between the two, a war won by Norway. Olaf's son by Geira, Sven, would begin building up a larger and larger army, and Olaf II, grandson of the first, would launch the invasion of Europe.
The first nation that would be invaded was Scotland. Scotland proved no match for Norway, however, when England, fearful they would be next, aided Scotland, the war escalated. The Normans, instead of attacking England, decided to invade Holland. They then made a truce with the Norse, swearing that they would not join the rumored anti-Norse Crusade if Norway did not invade them.