Saxony, home of Martin Luther, was the first country to be divided over the issue of the Protestant faith. While Ernestine Saxony became the heartland of the Reformation, the neighbouring principality of Albertine Saxony saw the beginnings of the Counter-Reformation. The two Saxonies provide almost perfect laboratory conditions for comparing contrary reactions to the Reformation. By investigating the lives, piety and politics of the Wettin princes, Frederick the Wise, John the Constant and George of Saxony the Reformation is revealed to have been a true game changer. Christian humanism, attempts at church reform and sympathy for the Reformation did not correlate neatly. Rather, the dynamics of religious conversion disrupted lines of continuity from the Middle Ages into the early modern era. That disruption testifies to the groundbreaking impact of Protestant ideas. At the same time, early resistance to Luther in Electoral Saxony proves that even in his homeland, Reformation and Catholic reform were alternatives right from the very beginning.