In the history of Europe, the struggle between the political power and the church for the dominance of the church has never stopped. After the split of the Eastern and Western Roman empires, the Eastern Church gradually formed a model of political power ruling the church, which has been in use ever since. However, due to the different preferences of emperors, the Eastern Church has been wavering between orthodoxy and heresy, and finally formed a mysticism tradition with low requirements.

At that time, there were five bishops in the Christian Church: the Bishop of Jerusalem, the Bishop of Antioch, the Bishop of Alexandria, the Bishop of Constantinople and the Bishop of Rome. The first four belong to the Eastern Church. Western churches United around the Roman church headed by the Bishop of Rome, resisted the interference of political forces in the ruling power of the church, formed the special status of the Bishop of Rome, and eventually became the Pope. Because "attack is the best defense", after centuries of struggle, the Pope gradually pursued political power, and finally through the Crusades, he disintegrated the power of western European princes against the Vatican and gained supreme privileges. Unfortunately, the Vatican gradually became corrupt, which eventually led to the Reformation.