So with the 90% authority requirement to mend the great schism it seems nigh impossible to do so. Has anyone gotten their religious authority that high to do it? And if so how?
Win in aAh yes, I forgot about building more church buildings. You would still have to get pretty lucky for 90% though right?
Win in a crusade: +10% moral authority. Building temple holding grants you a few percent. Winning Holy Wars will nab you 3% per war (you don't have to be the one to actually declare). Crushing Infidel Rebels nets you a few percent as well. Grab all the Holy Sites, relatively easy for a big ERE (even Rome should be a cake walk unless the HRE moved in). After all your conquests in the holy land expect plenty of Jihads and Holy Wars (including invasions and conquest CB which count as Holy Wars I believe) and (assuming you win them all) get a lot of moral authority. Converting Pagan rulers also gives a few percent and usually you'll see them convert even more rulers netting you that much more moral authority. In short, gogo authority farm. (Pope ain't got nothin' on dis!)