in the medieval states of the Iberian Peninsula:

(1) A corpus of general law relating to all the subjects of a kingdom. The first code of this type was the Lex Visigothorum, which came to be known in the 13th century as the Fuero Juzgo.

(2) A charter of feudal liberties granted to a particular province, class, or family.

(3) A municipal charter. This type of charter, the most common fuero, was usually granted in the name of the king and set forth the rights, privileges, and obligations of the inhabitants of an urban or rural community.

The development and proliferation of municipal fueros, which were particularly numerous from the 11th to 13th centuries, was associated with the Reconquest. As lands were won back from the Arabs, it became necessary to provide for their military defense and to develop their economies. The crown was compelled to provide incentives in order to attract settlers. In the early period of the Reconquest, municipal fueros merely fixed the location and boundaries of settlements; later, they defined the status of the settlers, made official the settlers’ exemption from corvée, and established rates of taxation. They also granted a measure of autonomy that included the right to elect a magistrate, freedom from seignorial jurisdiction, and the right to maintain a militia.

The fuero also defined the rights of the seignior over a particular community. The seignior could alter the fuero only with the approval of all the settlement’s inhabitants. Almost every city and the adjacent rural communities, hamlets, and villages had their own fueros. The cities jealously defended from encroachment by the crown the privileges granted under the fueros; alliances of cities, known as hermandades, were formed for this purpose.

Until the 14th century fueros of all types were the basic form of legislation in the states of the Iberian Peninsula. In the 14th and 15th centuries local fueros were of equal standing with royal codes of law; they were affirmed by the king, and new fueros were introduced. As the state government became centralized and royal power increased, the fueros lost much of their force. With the unification of Spain, they became nugatory.

The fueros are extremely important sources for the socioeconomic, political, and military history of medieval Spain.