== THEY MIXED UP THE FREDERICKS == 

 That's why the dates make no sense. Frederick Barbarossa was first. Frederick II of Swabia was, well, second. He ruled from Sicily, fought the Lombard League, united the empirefor awhile at leastand was crowned Holy Roman Emperor until a falling out with the pope ended with Frederick II of Swabia's excommunication. 

 They've got the father and son and I think even the grandfather all mixed up here and throughout all the Hauhenstaufen references. Sources? Tons of 'em. Look almost anywhere else.