Resum disponible en anglèsThis article has the objective of discussing the effective legislation in the territories of the Castile’s Crown in the beginning of the reign of Alfonso X, The Wise (1252-1284). In the middle of the thirteenth century, the territories belonging to the kingdoms of Castile and León, unified in 1230, by Fernando III (1217-1252), father of Alfonso X, had their own legislation, without a unity among the several juridical codes. In the kingdom of León, as well as in the territories belonging to him, the rights originating from the visigothic Liber Iudiciorum remained. In the territories of the Castile’s kingdom, the old Castilian right was in force, the Fuero Viejo of Castilla, codified in the beginning of the thirteenth century for Alfonso VIII (1158-1214). In the Andalusia territories that were incorporated to the Castilian crown by Fernando III, the Fuero Juzgo ruled, adapted to the local reality. The main task of Alofonso XI in the beginnning of his reign was the one of idealizing a project of juridical unification of the several codes on going in the territories of the Castile's Crown