Fueros of Navarre
The Fueros of Navarre were the laws of the Kingdom of Navarre up to 1841, tracing its origins to the Early Middle Ages and issued from Basque consuetudinary law prevalent across the Pyrenees. They were a sort of constitution which regulated the social order and defined the position of the king, the nobility, and the judicial procedures, which meant that the royal decisions needed to conform to the provisions set out by the charters.
The first such written document goes back to 1238. The next codifications are attested by modifications or amendments made by the regent of Navarre, Juan Martínez de Medrano, and his son, Álvaro Díaz de Medrano, commissioned in 1330 by King Philip III of Navarre to make the Fueros. The next modification or amendment was made in 1419. After 1512, Navarre was divided into two, with Upper Navarre a part of the nascent Kingdom of Spain and Lower Navarre an independent kingdom.
Upper Navarre
From 1515 until 1841, Upper Navarre was in effect an autonomous kingdom in personal union with the Spanish crown. It was allowed to retain a large degree of home rule, preserving much of the institutions of the independent kingdom, not exempt of tensions with the ever centralizing drive of Castile and attempts at reunification with independent Navarre to the north of the Pyrenees led by the Parliament. In 1528, the sitting at Pamplona authorised a simplified law code known as the Fuero Reducido. Although widely used, it was never confirmed by the king.A viceroy represented the Spanish monarch. The Cortes was the main legislative body, composed of three estates of clergy, nobles and burgesses. There was a Royal Council and a Supreme Court, as well as a Diputación del Reyno or Government of Navarre.