In 1016 boundaries had been drawn between Navarre and Castile; these boundaries made what would now be the Basque Country part of Navarre. This lasted until Guipuzcoa, Alava, and Vizcaya broke away from that kingdom amid a difficult political situation and became integrated into Castile under a treaty in 1200.
In 1016, boundaries were established between Navarre and Castile, which resulted in the Basque Country becoming part of Navarre. This arrangement lasted until Guipuzcoa, Alava, and Vizcaya broke away from Navarre and joined Castile under a treaty in 1200.