|←Author Index: Gr||Pope Gregory XIII
|Born Ugo Boncompagni, was Pope from 1572 to 1585.|
Works about Pope Gregory 
- “Pope Gregory XIII,” in Catholic Encyclopedia, 1913.
- “Gregory (Popes)/Gregory XIII” in Encyclopædia Britannica, (11th ed.), 1911.
|Works by this author published before January 1, 1923 are in the public domain worldwide because the author died at least 100 years ago. Translations or editions published later may be copyrighted. Posthumous works may be copyrighted based on how long they have been published in certain countries and areas.|