After the Pope, the College of Cardinals is the highest authority in the Roman Catholic Church. In addition to overseeing the major dioceses of the global church and managing the dicasteries of the Roman Curia, it is responsible for electing a new pope. Throughout its history, the College of Cardinals has undergone various changes. Particularly in the last two hundred years, the number of cardinals has increased from originally no more than 70 to currently over 200, and it has experienced significant internationalization. This work provides introductions to the history and present, as well as the roles and significance of the College of Cardinals, along with the biographies of all cardinals appointed from 1846 to 2012, thereby tracing the transformations and developments of this unique college.