Thomas Albert (Tal) Howard currently holds the Stephen Phillips Chair of History at Gordon College in Wenham, Massachusetts.

“How heavy the papal mantle weighs,” wrote Dante in his Divine Comedy.  The shepherding of some 1 billion Catholics is no simple business, so one cannot begrudge the frail Pope Benedict for stepping down.  Given the rarity of such an event, the recent media frenzy is understandable.  Much commentary has and will focused on Benedict’s legacy and the next papal election.  But given that traditionally only death separates a pope from office, the moment also calls for remembrance of those popes who finished their office under, well, grimmer circumstances.

The Apostle Peter, according to Catholics, was the first pope. Tradition claims he was crucified upside down in Rome because he felt unworthy to be crucified in the same manner as Christ.  Peter was the first of fourteen popes who are known or believed to have been martyred between the first and seventh centuries, the last being Martin I in 655.  In light of the expansion of Christianity during this time, the church father Tertullian’s famous line that the “blood of martyrs is the seed of the church” is not beside the point.

Things get shady from the ninth to the eleventh century.  At this time, the papal office became an object of contention among wealthy, feuding Roman families.  No less than about a third of the popes from 872 and 1012 died under mysterious, often macabre circumstances.  John VIII (872-82) was bludgeoned to death by members of his own entourage.  Stephen VI (896-97) was strangled.  Leo V (903) was deposed and likely murdered by order of his successor, Sergius (904-11).  John X (914-28) died from suffocation.  Because of popular distrust of Pope John XIV (983-84), the Antipope Boniface VII (974, 984-85) arrested him and placed him in the Rome’s Castel Sant’Angelo, where he died either from poison or starvation, depending on one’s sources.  (“Antipope” is a term used by the Church to speak of papal claimants of questionable legitimacy.)...