What if the Anglo Saxons have had a prominent role in establishing Duchies on the French coast instead of Normans , which are closely connected to the Saxon rule in Britannia ? Somehow the Norman expansion in Europe is halted early ( Normans might also fail in Italy) and the Anglosaxons are the real players. Also the Danish and Norwegian kingdoms and "Viking" raiders have had a more tough time with the Saxons. Thus no William of Normandy, no Hastings. Also the French Anglo-Saxons are Allies against Scandinanvian foes of Saxon rule ala Harald Haralda.