The Protestant Reformation was a 16th-century religious movement initiated by Martin Luther, who criticized the Roman Catholic Church's practices. His 95 Theses, aided by the printing press, spread rapidly, leading to his excommunication and the formation of Lutheranism. The movement diversified, inspiring other groups like Calvinists and Anabaptists, and became one of Christianity's major branches. By the 21st century, Protestantism had 800 million followers worldwide.

What was the main catalyst for the Protestant Reformation?

What document did Martin Luther create to outline his criticisms of the Catholic Church?

How did the advent of the printing press influence the spread of Luther's ideas?

What was the outcome of Luther's excommunication in 1521?

By the end of the 16th century, how had Protestantism diversified across Europe?