Number ten on our list of top ten controversial Catholic Popes is Pope Sergius III. The truth about Sergius III has been lost in the mists of time — he lived more than one millennium ago. But he is believed to have the dubious distinction of being the only Pope to order another Pope’s death: in 904, Antipope Christopher is believed to have been strangled to death on the order of Sergius III — who took control of the papacy that same year. His shady doings didn’t end there. Sergius III is rumored to have dallied with Marozia — the daughter of Theophylactus, a powerful count who helped the Pope expand into more territory — and to have fathered her son. That son, incidentally, went on to become Pope John XI.

No 9: Pope Leo X

No 1. Pope Stephen VI