What was the movement against the Roman Catholic Church that began in 1517 it resulted in the creation of Protestant churches?

Answer 1

This was the reformation.

People such as Jan Hus, Peter Waldo, and John Wycliffe had made attempts at reforming the Catholic Church but the reform movement really gained momentum When Martin Luther wrote and made public "The Ninety-Five Theses". This was a list of questions and propositions (mainly about the abuse of indulgences) for public debate. The selling/abuse of indulgences was a concern of Luther and others

There were many other teachings and practices of the Late Medieval Catholic Church that Luther and others were not happy with. For example, on a visit to Rome in 1510 Luther was greatly disappointed with the state of religion in Rome.

"He was favourably struck, indeed, with the business administration and police regulations of the papal court, but shocked by the unbelief, levity and immorality of the clergy. Money and luxurious living seemed to have replaced apostolic poverty and self-denial. He saw nothing but worldly splendour at the court of Pope Julius II., who had just returned from the sanguinary siege of a town conducted by him in person". - History of the Christian Church by Philip Schaff

Luther also believed the scriptures should be available for the common people to read, he translated The Bible into everyday German.

"Luther did not have in view the existence of an autonomous church alongside of the existing church. He desired the renewal of the church. He sought for good pastoral care, formulated the necessity for a better theology and expressed a desire for biblical piety". - Dr. Frank van der Pol from Christelijke Encyclopedie, (Kampen, 2005).