# John XXIII

> Italian bishop; Pisan antipope (1410–1415)

**Wikidata**: [Q294599](https://www.wikidata.org/wiki/Q294599)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Antipope_John_XXIII)  
**Source**: https://4ort.xyz/entity/john-xxiii-q294599

## Summary
John XXIII (born Baldassare Cossa) was an Italian bishop and Pisan antipope who served from 1410 to 1415. He is primarily remembered for his brief tenure as a rival claimant to the papacy during the Western Schism, a period of division within the Catholic Church.

## Biography
- Born: Unknown date and place
- Nationality: Italian
- Education: Studied at the University of Bologna
- Known for: Serving as the Pisan antipope during the Western Schism
- Employer(s): University of Bologna
- Field(s): Religious leadership

## Contributions
- Served as the Pisan antipope from 1410 to 1415, opposing the claim of Pope Gregory XII.
- His tomb, created by Donatello and Michelozzo, is located in the Baptistery of Florence and was completed in 1426.

## FAQs
- **Who was John XXIII?** He was an Italian bishop who served as the Pisan antipope from 1410 to 1415.
- **Where did John XXIII study?** He studied at the University of Bologna.
- **What is John XXIII known for?** He is known for his brief tenure as a rival claimant to the papacy during the Western Schism.
- **Where is John XXIII buried?** His tomb is located in the Baptistery of Florence, created by Donatello and Michelozzo.

## Why They Matter
John XXIII's brief tenure as antipope highlights the chaos and division within the Catholic Church during the Western Schism. His legacy is primarily tied to his role in this historical conflict, rather than any significant contributions to theology or governance.

## Notable For
- Served as the Pisan antipope during the Western Schism (1410–1415).
- His tomb, a collaboration between Donatello and Michelozzo, is a notable work of Renaissance art.

## Body
### Early Life and Education
- Baldassare Cossa, later known as John XXIII, was an Italian bishop.
- He studied at the University of Bologna, one of Italy's oldest universities.

### Religious Career
- In 1410, Cossa was elected as the Pisan antipope, opposing Pope Gregory XII.
- His brief tenure ended in 1415, marking the end of his role as a rival claimant to the papacy.

### Legacy
- His tomb, completed in 1426, is a significant monument in the Baptistery of Florence.
- The tomb was created by the artists Donatello and Michelozzo, contributing to the Renaissance art movement.

### Influence
- John XXIII's brief antipopehood was part of the broader Western Schism, a period of division within the Catholic Church.
- His legacy is primarily associated with his role in this historical conflict rather than any lasting theological or administrative contributions.

## References

1. Union List of Artist Names. 2012
2. Integrated Authority File
3. Catholic-Hierarchy.org
4. International Standard Name Identifier
5. Virtual International Authority File
6. Freebase Data Dumps. 2013
7. Dizionario Biografico degli Italiani
8. Vies des peintres, sculpteurs et architectes
9. LIBRIS. 2014
10. Dizionario di Storia
11. FactGrid
12. Bibliography of the History of the Czech Lands
13. HMML Authority File