Pope Urban VII was the last Pope to die in office. He was elected to the papacy on 15 September 1590 and died only 12 days later on 27 September 1590. His death was attributed to malaria, which he contracted during his brief papacy. Urban VII was known for his
From Wikipedia
Pope Urban VII, born Giovanni Battista Castagna, was head of the Catholic Church, and leader of the Papal States from 15 to 27 September 1590. His papacy is the shortest recognized in history.