Nafarroa under the French crown

Araba, Gipuzkoa and Bizkaia were gradually formed territorially during the Middle Ages, incorporating territories and managing to unify each territory politically. Until the 11th century, these territories, with their own institutions and laws based on customs, were governed by lords who offered vassalage to the monarch who exercised his dominion in the territory. At the end of the 11th century, the monarchs of Nafarroa and Castile followed a policy of founding towns in which to settle the royal dominion. Araba, Bizkaia, which was a Manor from the 11th century under the authority of the Haros, and Gipuzkoa fluctuated under the influence of Nafarroa and Castile, but became part of the Castilian crown in 1200. These territories conserved their autonomy, later based on the provincial privileges.

In the 14th and 15th centuries, the unification and political consolidation of the provinces of Araba, Bizkaia and Gipuzkoa were produced. In Gipuzkoa this processor was lead by the towns, with many privileges and great self-governing capacity, which were joined in brotherhoods. In Araba it was the lower rural nobles who carried out this task. In Bizkaia it was more complex to achieve the union of the four territories in which the Manor was divided.