If Philip of Swabia, King of the Germans, is not assassinated by the mad Count Otto VIII of Bavaria what would the future hold for the HRE and Sicily? By all accounts Philip was an effective ruler and true heir of his father (Barbarossa) and brother (the ambitious Henry VI), at the moment of his death he was very crush to crushing the Welf revolt let by his primary competitor for the German throne, Otto IV.
If he survives, goes on to secure the HRE and remains upon its throne what happens to Frederick II Hohenstaufen as he comes of age? Will Frederick rule over Sicily while Philip reigns in Germany? What sorts of tensions could one expect between these two rulers, especially if Philip eventually has a son who could claim the realm as his heir?