Constraints: (1) Economically, the Catholic Church is the largest feudal owner in Western Europe, occupying one third or even more of the land in various countries.

(2) Politically, the Catholic Church has established a hierarchical teaching system. Due to the weak kingship of various countries at that time, the Catholic Church became a huge international center of feudal rule in Western Europe.

(3) Social life and ideology, the Catholic Church controlled the daily life of the broad masses of the people and practiced strict spiritual dictatorship, which was the spiritual pillar of the feudal society in Western Europe.

Objection: (1) Economic aspect:14-15th century, the rise of capitalism and the popularity of mercantilism clashed with the church's light business thought.

(2) Politically,14-15th century, the rise of national thoughts and the formation of a nation-state demanded the "unification" of the Catholic Church in the Middle Ages. The emerging bourgeoisie needs to establish a unified domestic market and a secularized cultural system suitable for its own needs, while the church arbitrarily obstructs the unification of European countries and cruelly persecutes pagans and other progressives in order to safeguard its own interests. The Catholic church has become a major obstacle on the road to strengthening the royal power in western European countries.

(3) Culture: Renaissance advocated humanism and promoted religious reform. Renaissance is an ideological and cultural movement of the bourgeoisie against feudal theocracy, which liberated people's minds and had a great influence on the Catholic Church.

(4) The direct cause: the church is greedy and corrupt, and plunders the people in various names. The church's sale of "atonement vouchers" became the fuse.