The two leaders who were against the late medieval catholic church were Calvin and Luther.
Step-by-step explanation:
Martin Luther and John Calvin were the propellers of the religious revolution to reform the church. This reformation popularly gained the name protestant reformation. This revolution led to the foundation of Protestantism.
A major branch of the religion Christianity. This revolution took place during the 16th century. Luther was a theologian hence he studied the church from a different perspective he went to the theological roots.
He criticised the various practices of the church like indulgence system, and extensively opposed the idea of the pope being in charge of the purgatory and voiced his concern against many such ideologies that were actually not present in the original gospels.