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When Pope Benedict XVI announced that he would abdicate the papacy, he explained that "in today's world, subject to so many rapid changes...both strength of mind and body are necessary, strength which in the last few months, has deteriorated in me to the extent that I have had to recognize my incapacity to adequately fulfill the ministry entrusted to me." By becoming the first pope to resign since the 15th century, Benedict demonstrated a self-knowledge that is incredibly rare among leaders.