Symphony and the Alternative to Papal Supremacy

The emperor, as head of state, was expected to rule in harmony with the church's bishops. On the further end of the scale is Caesaro-papism, where the state dominates the religious establishment. We can learn from history what works and what doesn't, although historical examples cannot be completely mapped onto the future. I conclude that it's not at all evident, looking in history, that symphony works very well in practice for any length of time.