Which situation was a direct challenge to the political and religious authority of catholic church?

The Protestant Reformation, initiated by figures like Martin Luther in the 16th century, was a direct challenge to the political and religious authority of the Catholic Church. Luther's 95 Theses criticized church practices, particularly the sale of indulgences, and called for reforms that undermined the Church's power. This movement not only led to the emergence of Protestant denominations but also sparked significant political upheaval across Europe, as rulers and states began to question the Church's influence over governance and individual belief systems.