Harald's England is a timeline featuring a completely different history of Europe from the 11th century on. This TL will not be finished for a while, so please bear with me.
Point of Divergence
The first point of divergence in this timeline is the altered behaviour of the republics of Geno and Pisa following their joint conquest of Sardinia in 1017. OTL they fought over the island. In this timeline, they instead work out a system of joint vassalage, setting the foundation for a more permanent Genoa-Pisan alliance.
The second main point of divergence (which gives the timeline it's name) is William the Bastard's invasion of Britain being launched on schedule, leading to his defeat at the hands of Harold Godwinson. However, this in turn allows the other claimaint to the throne of England, Harald Hardruler, to defeat Godwinson and conquer his nation.