Pope Gregory XVI (d. 1846)
Pope Gregory XVI (Latin: Gregorius XVI; Italian: Gregorio XVI; born Bartolomeo Alberto Cappellari; 18 September 1765 – 1 June 1846) was head of the Catholic Church and ruler of the Papal States from 2 February 1831 to his death in 1846. He had adopted the name Mauro upon entering the religious order of the Camaldolese.

Strongly conservative and traditionalist, he opposed democratic and modernising reforms in the Papal States and throughout Europe, seeing them as fronts for revolutionary leftism. Against these trends, Gregory XVI sought to strengthen the religious and political authority of the papacy (see ultramontanism). In the encyclical Mirari vos, he pronounced it "false and absurd, or rather mad, that we must secure and guarantee to each one liberty of conscience." He encouraged missionary activity abroad and condemned the slave trade. However, his harsh repression, financial extravagance and neglectfulness left him deeply unpopular domestically.

He is the most recent pope to take the pontifical name "Gregory", and the most recent pope who was not a bishop when elected. He was, until the accession of Pope Francis in 2013, the most recent pope to have been a priest of a religious order.