ABSTRACT
During the last centuries of the Middle Ages, the Castilian monarchy, like other western European monarchies, progressively developed a systematic fiscal system, that is, a group of taxing procedures and collection techniques that combined to assure that no source of wealth remained untapped. Taxation was an expression of sovereignty. It is thus critical to determine what was the king's right to tax these subjects, what elements constituted the tax base and the base of other state revenues, and the mechanisms that were created to collect taxes. The origins of sovereign power of the kings of Castile derived from Roman law and imperial inheritance transmitted by the Visigoths. Alfonso X wanted to take fiscal advantage of the development of transhumance on the peninsula that saw flocks of sheep travel on roads that connected summer pastures in Castile and Leon with winter pastures in Andalusia. The taxation system therefore helped the aristocracy prevail in the second half of the fifteenth century.
