The Apostolic Chancery (Latin: ''Cancellaria Apostolica''; also known as the "Papal" or "Roman Chanc(ell)ery") was a dicastery of the Roman Curia at the service of the Supreme Pontiff of the Roman Catholic Church. The principal and presiding official was the Cardinal Chancellor of Holy Roman Church who was always Cardinal-Priest of the Basilica di San Lorenzo in Damaso. The original, principal function of the office was to collect money to maintain the Papal Army. Pope Pius VII reformed the office when Emperor Napoleon I of France obviated the need for Papal armies. In the early 20th century the office collected money for missionary work. Bl. Pope Paul VI abrogated the Cancellaria Apostolica on 27 February 1973. Its obligations were transferred to the Secretariat of State.
The Cancellaria Apostolica was of ancient origin in its essence, but it derived its name from that of civil "", including that of the Imperial Chancery. The primacy of the Supreme Pontiff required that he have in his service officials to write and transmit his answers to the numerous petitions for favours and consultations addressed to him. Throughout its duration the office was reformed numerous times.
The Apostolic constitution Etsi ad Singula of Pope Clement VII of 5 July 1532 provided the cardinalatial title of the Basilica di San Lorenzo in Damaso to the Chancellor.
After Pope Martin V had instituted a large number of offices in the Cancellaria, Pope Sixtus V placed many of them in the class of "vacabili", i. e. venal offices (a practice also of secular courts, e. g. those of France, even under the absolutist King Louis XIV). The reclassification of many of the offices of the Cancellaria as vacabili was motivated by the need of the Pope for money. The Pope was often compelled to defend the Church by waging war, equipping martial expeditions, or at least financially assisting the princes who waged such wars at his exhortation, but the Papal treasury was often insufficient to defray even the expenses of the Papal States. Accordingly, the Popes resorted to the expedient of selling several lucrative offices of the Roman Curia to the highest bidder; however, these sales were not of the offices per se, but of the receipts of the offices, e. g., the taxes paid for the favours that were granted through the pertinent office.