A comparison of Martin Luther and John Calvin shows that they stand in line with historic Christianity and share core Reformation principles. Abuses in the Catholic Church and indulgences are among the main reasons why Luther broke with the church in which he grew up. Luther gave the impetus for other Reformations and theological movements, in particular Zurich, represented by Heinrich Bullinger with his contribution to covenantal thought, and Geneva, where Calvin through his Institutes crystallized Reformed theology. While Luther showed some appreciation for Calvin, Calvin, without idealizing Luther, acknowledged his towering influence. Luther and Calvin left their mark in areas such as theology, the church and worship, society, and Western history and culture.