Full Name: Ugo Boncompagni
Why Famous: Gregory was the head of the Catholic Church for thirteen years, but his best-known move was the creation of the Gregorian calendar, which remains in use as the internationally accepted civilian calendar to this day.
Gregory also embarked on an administrative reform of the church, support of arts and sciences within the Vatican and encouraged attempts to overthrow Queen Elizabeth I of England.
He died in 1585 and was succeeded by Sixtus V.
- 1577-10-25 Pope Gregory XIII asks renewal of ecclesiastical hymns
- 1582-02-24 Pope Gregory XIII announces New Style (Gregorian) calendar