… Castile This division creates the political…

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• Castile

This division creates the political geography of Iberia that will persist until its unification under the Catholic Monarchs in the 15th century.

Sancho’s Enduring Influence

Sancho III strengthens and stabilizes the Kingdom of Navarre, ensuring its independence for the remainder of the Middle Ages. However, by dividing his realm, he isolates Navarre and limits its ability to expand southward against the Muslims, shifting the Reconquista’s momentum to León, Castile, and Aragón.

Despite the disintegration of his empire, Sancho III "the Great" leaves behind a powerful dynasty, and his reign defines the political and territorial structure of Iberia for centuries to come.