The Papacy is one of most powerful institutions in the history of religion. During the medieval period it had the authority to condemn kings and queens, define what was Christian and what wasn't, and even organize huge military campaigns. But how did the Papacy rise to become this almost invincible seat of power? Where did it originate from? And from what source did it draw its legitimacy? James Aiken Wylie, the brilliant scholar of church history, casts his critical eye over the Papacy and uncovers the answers to these questions. Looking first at ancient Rome, Wylie studies how the Papacy emerged in the aftermath of the collapse of the Western Roman Empire. Wylie's work explores how the Papacy grew in power through the course of the Middle Ages as it worked to legitimize itself by allying with powerful rulers such as Charlemagne. The work and acts of some important individual popes, such as Gregory VII and Innocent III are studied in more detail, providing the reader with insight into what sort of men rose to the height of power in the Roman Catholic Church. Wylie exposes how the bureaucracy of the Papacy developed as the curia grew in power and the central ordinances and regulations of canon law were laid out. Particularly fascinating is Wylie's analysis of why the Papacy struggled to cope with the Protestant Reformation that erupted in the sixteenth century and tore Christianity in two. Indulgences and the concept of purgatory, as well as many other beliefs and actions, that were held and taken by the Papacy are questioned by Wylie through the course of the book. This is essential reading for anyone interested in the Papacy and how it has changed through the course of its long history. James Aitken Wylie was a Scottish historian of religion and a staunchly Presbyterian minister who had a critical view of the Catholic Church. He was a prolific writer and is most famous for his twenty-four book long The History of Protestantism, which was first published in 1878. Wylie died before completing his History of the Scottish Nation in 1890.