Treaty signed on February 16, 1267 between King Alfonso X of Castile and King Afonso III of Portugal
Established the permanent border between Portugal and Castile along the Guadiana river, forming the basis for the 1297 Treaty of Alcañices.
Key Facts
- Date signed
- 16 February 1267
- Signatories
- Alfonso X of Castile and Afonso III of Portugal
- Border agreed
- Course of the Guadiana river, mouth to river Caia
- Knights pledged by Denis of Portugal
- 50 knights
- Border validity
- Remained until 1801
- Follow-on treaty
- Treaty of Alcañices, 1297
By the Numbers
Location
Cause → Event → Consequence
Ongoing territorial disputes between Castile and Portugal over the Algarve and the status of Portuguese kings as vassals of León created a need for a formal resolution. Alfonso X held claims to the Kingdom of the Algarve, while Portugal sought recognition of full sovereignty and clear territorial boundaries.
On 16 February 1267 in Badajoz, Alfonso X of Castile and Afonso III of Portugal signed a treaty establishing mutual assistance and friendship. Alfonso X renounced rights to the Algarve, Portugal's vassalage to León was formally ended, and the Guadiana river was fixed as the border between the two kingdoms.
Portugal ceded some territory east of the Guadiana to Castile, while gaining confirmed sovereignty and a defined border. The treaty laid the groundwork for the Treaty of Alcañices in 1297, which settled the Portuguese-Castilian border for nearly five centuries until 1801, when a later Treaty of Badajoz altered it.
Political Outcome
Alfonso X renounced claims to the Algarve; Portuguese vassalage to León ended; Guadiana river fixed as the Castile-Portugal border.
Portugal partially subordinate to León; Castilian claims over the Algarve unresolved
Portugal recognised as fully sovereign; border with Castile formally delimited along the Guadiana