Religion was changed at this time thanks to Martin Luther and his 95 thesis, with this he posted and said that the church was corrupted and that the vast majority of its belief were humans rather than God's. Some of these beliefs were: some of the sacraments and the indulgencies, these last were pieces of appear signed by the pope saying that you or your relative was saved.
Now religion was not private but it was more focus on an personal relationship more than to been devoted to an organization or church. At this time nationalism also was arising and the power of secular leaders growth and many little towns were against the fee that Rome charged them.
The reformation brought a new era to the church but this could only be supported by propaganda and this propaganda was aided by the printing of books and graphics arts. Many German artist had tendencies to do focus on line over form but at this time they stared using woodblocks and engraving. This techniques let artist to express with greater realism because they were able to do their artwork in 3d. we also see that before the reform of the church artist focused a lot on saints and their role in their paintings but at the reformation time, German artist became more interested in the life of Jesus Christ instead of the saints because Lutherans rejected the role they played as intermediates in the catholic church. So, we see reformation principles in art at this century because, because of the work that Martin Luther did the bible was translated to German and it was printed so everyone could have access to it; also painted focused more on Jesus than in the saints and the arise of new media took place at this century too.