Gregorian calendar

====First printed Gregorian calendar====
[[File:Reforma Gregoriana del Calendario Juliano.jpg|thumb|
''Lunario Novo, Secondo la Nuova Riforma della Correttione del l'Anno Riformato da N.S. Gregorio XIII'',{{efn|name=Lunario|"New Almanac according to the new reform for the correction of the year, [as] reformed by His Holiness Gregory XIII".}} printed in [[Rome]] by Vincenzo Accolti in 1582, one of the first printed editions of the new calendar]]
A month after having decreed the reform, the pope (with a brief of 3 April 1582) granted to one Antoni Lilio the exclusive right to publish the calendar for a period of ten years. The {{lang|it|Lunario Novo secondo la nuova riforma}}{{efn|name=Lunario}} was printed by Vincenzo Accolti, one of the first calendars printed in Rome after the reform, notes at the bottom that it was signed with papal authorization and by Lilio (''Con licentia delli Superiori... et permissu Ant(onii) Lilij''). The papal brief was revoked on 20 September 1582, because Antonio Lilio proved unable to keep up with the demand for copies.<ref>{{cite book| last1=Mezzi |first1=E. |last2= Vizza | first2=F. | title= Luigi Lilio Medico Astronomo e Matematico di Cirò | publisher= Laruffa Editore |location = Reggio Calabria | year=2010 |pages=14, 52 |isbn=9788872214817 }} citing as primary references: {{lang|it|Biblioteca Nazionale Centrale di Firenze}}, Magl. 5.10.5/a, [[Vatican Apostolic Archive]] A.A., Arm. I‑XVIII, 5506, f. 362r.</ref>