Treaty of Sahagún

Timeline

1. 1157–1158Sahagún · Castile and LeónAfter Alfonso VII's death the empire split into Castile and León; the two brothers concluded a treaty at Sahagún monastery, confirming their mutual obligations in writing and seeking to avoid civil war over the succession.
2. 1158Sahagún · Castile and LeónThe treaty forbade either side from allying with Alfonso I of Portugal and provided that if Portugal were conquered its territory would be divided; León obtained priority of conquest toward the Muslim cities of Niebla, Mérida, Badajoz, Évora, and Silves, posing a serious threat to Portugal.
3. c. 1158–1160Iberian Peninsula · Iberian PeninsulaAfter Sancho III's sudden death Castile fell into a minority regency crisis; Ferdinand II tore up the treaty, invaded Castile, and triggered the Portuguese-Leonese War of 1158–1160; by late 1160 the two sides concluded a new treaty at Serranova and elsewhere, and the Treaty of Sahagún became a historical document.