Dictionary.net

the pope who sponsored the introduction of the modern calendar (1572-1585)

the pope who fought to establish the supremacy of the pope over the Church and the supremacy of the Church over the state (1020-1085)

(Roman Catholic Church) a pope distinguished for his spiritual and temporal leadership; a saint and Doctor of the Church (540?-604)

the pope who sponsored the introduction of the modern calendar (1572-1585)

the pope for whom Gregorian chants were named (circa 540-604)

the pope who fought to establish the supremacy of the pope over the Church and the supremacy of the Church over the state (1020-1085)