Pope Gregory XIII
Commissioned the Gregorian calendar and reformed the Catholic Church.
Pope Gregory XIII, born Ugo Boncompagni on 7 January 1502 in Bologna, led the Catholic Church and ruled the Papal States from 13 May 1572 until his death on 10 April 1585. His most lasting achievement was commissioning the Gregorian calendar, which is still the standard civil calendar worldwide.
The son of Cristoforo Boncompagni and Angela Marescalchi, Ugo studied law in Bologna, graduating in 1530, and later taught jurisprudence. Among his students were Cardinals Alexander Farnese, Reginald Pole, and Charles Borromeo. Before taking holy orders, he had an illegitimate son, Giacomo, with Maddalena Fulchini, making him the last pope to have children. In a 1552 document, Ugo formally acknowledged paternity of Giacomo, conceived in Bologna in 1547, to secure the boy's inheritance after his own father's death.
At 36, Pope Paul III called him to Rome, where he served as first judge of the capital, abbreviator, and vice-chancellor of Campagna e Marittima. Pope Paul IV assigned him as datarius to Cardinal Carlo Carafa's suite. Pope Pius IV made him Cardinal-Priest of San Sisto Vecchio and sent him to the Council of Trent. He also acted as legate to Philip II of Spain, investigating the Archbishop of Toledo, and built a close relationship with the Spanish king that later shaped his foreign policy.
After Pope Pius V died, the conclave elected Cardinal Boncompagni in under 24 hours, a swift decision many historians link to Spanish backing. Charles Borromeo and reform-minded cardinals supported him, and the Spanish faction found him acceptable due to his success as a nuncio in Spain. He took the name Gregory XIII in honor of Pope Gregory the Great.
As pope, Gregory XIII focused on reforming the Church, implementing the Council of Trent's recommendations. He required cardinals to reside in their sees, updated the Index of Forbidden Books, and sponsored a new edition of the Corpus juris canonici. He abolished the Cardinals Consistories, replacing them with colleges assigned specific tasks, and was known for his fierce independence, rarely seeking advice. Papal power grew while the cardinals' influence shrank. In 1580, he established the Discalced Carmelites as a distinct province within the Carmelite Order.
He generously supported Jesuit colleges in Rome, especially the Roman College, which became a leading European learning center and later the Pontifical Gregorian
- born
- 7 January 1502, Bologna
- died
- 10 April 1585
- field
- Catholic Church, Papal States
- nationality
- Italian
- known_for
- Gregorian calendar, reform of the Catholic Church, patronage of Jesuit colleges
Lore & Background
Ugo Boncompagni was born in Bologna, studied law, and graduated in 1530. He taught jurisprudence, counting among his students Cardinals Alexander Farnese, Reginald Pole, and Charles Borromeo. Before taking holy orders, he had an illegitimate son, Giacomo, with Maddalena Fulchini, making him the last pope to have left issue. At age 36, he was summoned to Rome by Pope Paul III and held successive appointments as judge, abbreviator, and vice-chancellor. Pope Pius IV made him Cardinal-Priest of San Sisto Vecchio and sent him to the Council of Trent. He also served as legate to Philip II of Spain.
After the death of Pope Pius V, the conclave chose Cardinal Boncompagni in less than 24 hours, a brevity many historians attribute to Spanish backing. He took the name Gregory XIII in homage to Gregory the Great. As pope, he implemented the recommendations of the Council of Trent, mandated that cardinals reside in their sees, and updated the Index of Forbidden Books. He abolished the Cardinals Consistories, replacing them with Colleges, and established the Discalced Carmelites as a distinct province in 1580.
Gregory XIII was a generous patron of Jesuit colleges, notably the Roman College (now the Pontifical Gregorian University), and founded seminaries for training priests, beginning with the German College. In 1575, he gave official status to the Congregation of the Oratory. He commissioned artists to decorate the Vatican, including The Gallery of Maps, and transformed the Dominican studium into the College of St. Thomas in 1580.
Reader's Guide
Pope Gregory XIII's most enduring legacy is the Gregorian calendar, which he commissioned and enacted via the papal bull Inter gravissimas on 24 February 1582. The calendar corrected the drift of the vernal equinox by removing ten days (4 October 1582 was followed by 15 October) and adjusted leap-year rules. Though initially met with popular opposition and slow adoption by Protestant and Eastern Orthodox nations, it eventually became the internationally accepted civil calendar. Beyond the calendar, Gregory XIII strengthened papal authority, reformed church administration, and promoted Catholic education through Jesuit institutions. His foreign policy focused on countering Protestantism, including support for expeditions to Ireland during the Desmond Rebellions. His pontificate marked a period of centralization and renewed Catholic vigor after the Council of Trent.
Did You Know?
- He was the last pope to have left issue, an illegitimate son named Giacomo Boncompagni.
- The conclave that elected him lasted less than 24 hours.
- He established the Discalced Carmelites as a distinct province within the Carmelite Order in 1580.
- The Gregorian calendar was initially opposed by many who feared landlords would cheat them of rent.
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