Joseph McCabe 
Crises in the History of the Papacy [PDF ebook] 

Probably no religious institution in the world has had so remarkable a history, and assuredly none has attracted so large and varied a literature, as the Papacy. This book contains a study of twenty famous popes whose careers and whose influence were important in the development of the church and in the history of the world. It provides a view of the Papacy from the early 3rd to the early 20th century.