great heathen army

During the time of the Great Heathen Army's invasion of England, a great king named Rhodri was busy uniting Wales. IOTL he was killed in a war with Mercia, and his realm was divided. What would happen if Mercia never interfered, or was crushed when they did? If he united Wales, how might he deal...

So, suppose that kings Alfred and Aethelred of Wessex are much less lucky in beating back the Great Heathen Army, and see their lands conquered by it instead. England becomes "Jorvik", a brand new Norse state, or collection of warlord states, in the late 9th century. So, what are the effects on...