Luther did not intend a division of the church with his actions. What he had aimed for was a reformation within the church that would put the focus back on the Confession, the Sacrament of Penance. His fundamental criticism fell on sympathetic ears with several territorial lords and theologians, which lead to the introduction of the Reformation in several lands and territories of lords and therefore to the decay of the Christian unity of faith.
At the same time a century of religious wars where Catholics fought against the Protestants and Reformed countries began. Millions of people were killed and much of Europe was devastated. Only the Piece of Westphalia in 1648 set an end to the battles among Christians and at the same time strengthened the division of the denominations.
Today, Protestants and Catholics have learned to openly and peacefully dispute about which is the right approach to things. Today the motto is „unity in diversity”: Christians may have different traditions and belong to different organizations, but mutual respect and a discursive approach to coexisting is a mutual interest.