Pope Gregory XIII (Latin: Gregorius XIII; 7 January 1502 – 10 April 1585), born Ugo Boncompagni, was Pope 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 day.

During his pontificate, Gregory fostered cultural patronages associated with his papacy. He strengthened many ecclesiastical and diplomatic envoys to Asia, namely the islands of Japan and the Philippines. He was also the first Pope to bestow the Immaculate Conception as Patroness to the Philippine Islands on 9 February 1579 through the Papal Bull Ilius Fulti Præsido.

Early biography

Youth

Ugo Boncompagni was born the son of Cristoforo Boncompagni (10 July 1470 – 1546) and of his wife Angela Marescalchi in Bologna, where he studied law and graduated in 1530. He later taught jurisprudence for some years, and his students included notable figures such as Cardinals Alexander Farnese, Reginald Pole and Charles Borromeo. He had an illegitimate son after an affair with Maddalena Fulchini, Giacomo Boncompagni, but before he took holy orders.

Gregory has been the name of sixteen Roman Catholic Popes and two Antipopes. The Latin name is Gregorius.