Although a highly visible part of the ecclesiastical furniture of the Roman Catholic Church and the Vatican for thirteen centuries, surprisingly little has been written about cardinals or (apart from some notable individual biographies), about the men who became ‘papal princes’. The cardinals of the Roman Church are “the nearly men” of Catholicism - those whose office since the 11th century has been chiefly to choose the Pope, following efforts to wrest this power from Rome’s nobility and militia. This compelling history traces the origins and growth of the office of cardinal and tells the stories of some of the remarkable (for all kinds of reasons) men who have worn the red cap, coveted by some, refused on occasion and sometimes laid down in exchange for marriage, though one maverick got wed in his red hat.