Pope Celestine V

Pietro da Morrone was a hermit who founded his own monastic order, content in solitude until cardinals deadlocked for two years chose him in 1294 - the last pope elected outside a conclave. He lasted five months. Nearly every decree he issued was annulled by Boniface VIII, except one: the right of a pope to abdicate. On 13 December 1294, a week after codifying that power, Celestine used it, citing his longing for the humble life he'd left. Boniface imprisoned him in Fumone castle to prevent rivals from installing him as antipope. He died there on 19 May 1296, was canonized seventeen years later, and no pope since has taken his name.