Sixtus V was born to peasant family, and worked as a swineherd during his adolescence. He was drafted into a Franciscan monastery while young, and rose quickly through the church ranks. As an enemy of Gregory XIII, he had to fake retirement for a while, but then was elected as his replacement.

While Pius and Gregory had worked to reform the papal court and church, they had largely ignored the area of Italy which they controlled, the Papal States. These had run wild with bandits, but Sixtus cleaned them up with fairly brutal force. He then went on a building spree, beautifying Rome with new construction but trampling on the ancient structures. Sixtus also excommunicated Queen Elizabeth I of England, who was busy administrating her own Church of England.

He ruled from 1585 to 1590.