The Tree of Europe · Person

Gregory X

Elected pope after an exceptionally long vacancy, he promoted new rules for papal elections at the Council of Lyon in 1274, laying the foundations of the conclave system.

c. 1210 – 1276PopeVisconti

Explore this family · Spanish Atlas Back to people

Posthumous portraitGregory XBuonamico Buffalmacco · Fourteenth centuryArezzo CathedralPublic domain · PDM 1.0 · Source

This complete profile is available in English. Bibliographic titles retain their original language. Links marked ES open the Spanish edition.

Historical profile

Key details

Birth: 1210 Approximate

Death: 1276 Documented

Role: Pope

Other recorded names: Teobaldo Visconti · Gregorio X (Teobaldo Visconti)

Dynasty: Visconti

Territories: Papal States (ES)

Recorded governments and reigns

Pope · Papal States · Pontificate Pending review1271–1276Effective rule

Family network

Recorded relationships

No direct relationships are recorded for this person.

Documentation

Sources for this profile

Biographical and contextual references in their original language. Sources and methodology.

Evidence for this profile

3 recorded claims · 2 without a claim-specific source. Context references do not by themselves verify every fact.

Dates (1/2 with a precise source)

BirthApproximate
1210
A precise source has not yet been added.
No individual review recorded ·
DeathDocumented
1276
The authority record gives the death as 1276.
Deutsche Nationalbibliothek · GND · Gregor X., Papst · Vital data: death date
Reviewed on 2026-10-17 by El Árbol de Europa ·

Governments (0/1 with a precise source)

GovernmentPending review
Pope · Papal States · 1271–1276
A precise source has not yet been added.
No individual review recorded ·

Biographical and contextual references (3)

Editorial history

2026-10-12 · Claim registry added; existing historical data kept. Specific sourcing remains to be reviewed.
2026-10-08 · Claim registry added; existing historical data kept. Specific sourcing remains to be reviewed.
2026-10-04 · Claim registry added; existing historical data kept. Specific sourcing remains to be reviewed.
2026-10-04 · Claim registry added; existing historical data kept. Specific sourcing remains to be reviewed.
2026-10-03 · Claim registry added; existing historical data kept. Specific sourcing remains to be reviewed.
2026-09-30 · The duchy is limited to Dijon and Autun; each other fief now enters the map only under its dated ruler. John III of Namur and the Nevers/Rethel branch were added. The previous shape combined later counties and unrelated lands as if all belonged to the duchy from 1363.
2026-09-28 · Claim registry added; existing historical data kept. Specific sourcing remains to be reviewed.