https://en.wikisource.org/wiki/Catholic_Encyclopedia_(1913)/Pope_Gregory_XV
Catholic Encyclopedia (1913)/Pope Gregory XV - Wikisource, the free online library
catholic encyclopediagregory xvthe freepope
https://pam.wikipedia.org/wiki/Pope_Gregory_XV?action=edit&redlink=1
Creating Pope Gregory XV - Wikipedia
gregory xvcreatingpopewikipedia
https://www.vatican.va/content/vatican/en/holy-father/gregorio-xv.html
Gregory XV
gregoryxv