(Hey Lulu! I grew up in SC.)
Two books by Barbara Tuchman:
A Distant Mirror and
The March Of Folly.The first is a history of the 14th Century, when one Pope sat in Rome and another in Avignon, each cheerfully excommunicating all of the other's followers. And STILL nobody caught onto the scam. (Sorry for the snark, I'm an atheist.) It's not a papal history of the times, but the story of the Dueling Popes is covered in detail.
The second is an inquiry into why nations willingly act against their own best interests. (And it's a shame Tuchman didn't live long enough to write about the Iraq cluster-Cheney.)
One long section in
March Of Folly describes how the 16th-century Popes provoked the Protestant Reformation by their own greed and arrogance. (The other sections deal with Britain losing its American colonies, and the U.S. in Vietnam.)
David I. Kertzer's
The Popes Against The Jews: an example of an author who DID get to the primary sources. Kertzer was given access to the Vatican's previously "secret" files. He traces the long, sorry history of anti-Semitism in the Catholic Church, using sources which include the official Vatican and Jesuit newspapers. (Where did the Jews first have to wear gold stars to identify them? In the Papal States...)
Finally, a wild card:
The Story Of Stupidity by James F. Welles. A sort of general history of human stupidity, from the ancient Greeks to modern times.
You can check out the Welles book online, here:
http://www.stupidity.com/story1final/