The Reformation had a profound impact on the Catholic Church, leading to significant theological, political, and social changes. Initiated by figures like Martin Luther in the early 16th century, the Reformation challenged the Church's teachings and practices, leading to the birth of Protestantism. The subsequent Counter-Reformation sought to address some of the criticisms and reform internal practices within the Catholic Church. This period resulted in the loss of credibility for the Church, a decrease in its political power, and the fragmentation of Western Christianity, deepening the divide between Protestant and Catholic populations in Europe.