How did martin luther's view of the catholic church change in his lifetime?

Luther was devoted to the Catholic Church during his early years, growing up with a Catholic education.  His feelings of guilt over his own sins drove him to enter a monastery, following a path the church provided for devoting oneself to God.

During his years as a monk, he was trained in theology to become a faculty member at the University of Wittenberg.  The more he studied the Bible itself, the more he saw differences between biblical teaching and the policies and practices of the Catholic Church.  He began to protest against some of what he saw wrong in the church -- not wanting to break away from the church, but to correct problems.

The higher officials of the Roman Catholic Church reacted violently against Luther, excommunicating him and wanting to silence him and even put him to death.  This solidified Luther's conviction that the Catholic Church was wrong, and he became more and more antagonistic against the officialdom of the Roman Church.  He went as far as to declare the office of the pope as the Antichrist.