- Giovanni Battista Castagna
Son of Cosimo, a nobleman of Genoa, Italy, and Costanza Ricci. Doctor of civil and canon law. Auditor for his uncle, Girolamo Cardinal Verallo, whom he accompanied as part of the papal delegation to France. Appointed referendary of the Segnatura di Giustizia and Archbishop of Rossano, Italy on 1 March 1553 for Pope Julius III. Ordained on 30 March 1553. Ordained bishop and archbishop on 4 April 1553. Governor of Fano, Italy in 1555. Governor of Perugia and Umbria in the reign of Pope Paul IV. Peacemaker between Terni and Spoleto for Pope Pius IV. Assisted at the Council of Trent; president of several congregations there. Worked in Spain with the future Pope Gregory XIII. Papal nuncio to Spain for seven years. Papal nuncio to Venice. Governor to Bologna in 1577. Papal legate to Cologne in 1578. Consultor of the Holy Office and the Ecclesiastical State. Created cardinal–priest on 12 December 1583 by Pope Gregory XIII. Papal legate to Bologna on 8 October 1584. Advisor to Pope Sixtus V. Inquisitor-General on 19 November 1586. 228th pope in 1590.
Noted for his charity to the poor. He subsidized Roman bakers so they could sell bread under cost, and restricted the spending on luxury items for members of his court. Subsidized public works projects. Forbade nepotism within the Curia and the use of the title “Excellence” for relatives of the pope. His reign lasted a mere twelve days; he died before his official coronation. His estate, 30,000 scudi, was bequeathed to the Archconfraternity of the Annunciation to use as dowries for poor girls.
- 27 September 1590 at Rome, Italy of malaria
- buried in the Vatican Basilica
- re-interred in the church Santa Maria sopra Minerva