Not quite. The actual premise is simpler; Harold wins Hastings. Meanwhile he goes on an attempted vengeance conquest against Scandinavia, but has a hard time holding on to these pocessions. Later he would intermarry with the Swedish rulers, cementing his hold here.
Meanwhile, he allied with the French king and destroyed Normandy, but then had to deal with a papal excommunication. Hence, he and France established the Avignon papacy a few hundred years earlier and they marched on Italy and the semi-allied Holy Roman Empire. France conquered Northern Italy, while England took Hannover and Pommerania; the Holy Roman empire fell apart.
The status quo went on for a little while, when suddenly a revived Holy Roman Empire, allied with the Papacy and the Spanish kingdoms struck. However, their attacks ended in utter failiure, the Muslims advancing to destroy the Christian Spaniards while they were occupied, and the Holy Roman Empire was almost entirely annexed by Britain and a new vassal in Bohemia.
Meanwhile, the Magyars rose to prominence again, building an Empire that consisted of Croatia, Serbia, Hungary, Romania, and Austria.
Then Frederick Barbarossa, or his equivalent, rose in the great Saxon rebllion and established his own empire, which triggered the Hundred Years War, after which the Mongols invaded.
That's all from memory, though, so there's probably inconsistancies with my initial description.
