Answer: During the Protestant Reformation, men like Martin Luther, John Calvin, and Ulrich Zwingli sought to reverse Catholicism’s changes to Christian doctrine and end abusive practices such as the selling of indulgences. For centuries, groups within Western Christianity had objected to the heretical drift of the Roman Church and sought to correct it. Among these were the Anabaptists, a loose collection of reform-minded Christians within the church who greatly objected to doctrines such as infant baptism and a centralized church. As the Reformation continued, groups like the Anabaptists considered the steps taken by Luther, Calvin, and Zwingli to be insufficient. They pushed for even more drastic separation from Catholicism—not just Reformation, but “Radical Reformation.”

The Radical Reformers took issue with mainstream Reformers over several key issues. One of these was the doctrine of infant baptism, a Catholic innovation maintained by denominations such as Lutheranism. The name Anabaptist refers to being “baptized again,” and the Radical Reformers insisted that Christianity return to its earlier understanding of baptism for believers only.

The Radical Reformation also opposed mainline Reformers over the relationship between church and state. Most of the major Reformers felt that church and state were intertwined and that it was appropriate to use politics and law to enact both church and social reform. Calvin, Luther, and Zwingli’s process is sometimes referred to as the Magisterial Reformation, for this reason. In parallel, most Reformers maintained support for a highly centralized church structure. Radical Reformers, on the other hand, felt that church and state should be separated and that each individual church was accountable only to Christ and Scripture, not to any human institution.

The doctrinal beliefs of the Radical Reformation predated the work of men like Martin Luther and John Calvin. While the Anabaptists were not literally part of a separate denomination before the Reformation, their disagreement with the Magisterial Reformers moved them in that very direction. Ultimately, these differences led some change-minded Christians to dissociate themselves from both Roman Catholicism and the majority of the Protestant Reformers.