|←Author Index: Jo||Pope John XXI
|Pope from 1276 to 1277.|
Works by John XXI 
Works about John XXI 
- “Pope John XXI (XX),” in Catholic Encyclopedia, 1913.
- “John XXI.” 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.|