Pope Gregory XIII

Pope Gregory XIII
Bishop of Rome
Diocese	Rome
See	Holy See
Papacy began	13 May 1572
Papacy ended	10 April 1585
Predecessor	Pius V
Successor	Sixtus V
Orders
Ordination	c. 1558
Consecration	1558
Created cardinal	12 March 1565 by Pius IV
Personal details
Birth name	Ugo Boncompagni
Born	7 January 1502 Bologna, Papal States
Died	10 April 1585 (aged 83) Rome, Papal States
Previous post	Bishop of Vieste (1558–1560) Legate to Spain (1565) Prefect of the Apostolic Signatura (1565) Cardinal-Priest of San Sisto Vecchio (1565–1572)
Motto	Aperuit et clausit ("Opened and closed")
Coat of arms
Other popes named Gregory

Pope Gregory XIII (Latin: Gregorius XIII; 7 January 1502 – 10 April 1585), born Ugo Boncompagni, was the head of the Catholic Church from 13 May 1572 to his death in 1585. He is best known for commissioning and being the namesake for the Gregorian calendar, which remains the internationally accepted civil calendar to this date.