This chapter is based on two pillars: first, a state of the question about the mayorazgos (entailed estates) in the Crown of Castile in the late Middle Ages, before the promulgation of the Laws of Toro (1505); second, a commentary on the literature on the important lineage of the Fernández de Velasco with a Digital Humanities proposal for the systematization of the data on the entailments of this noble family. Thus, it is proposed to advance in the knowledge of transversal elements of the subject, the application of comparative studies and new ways to analyze the mountains of data generated by the entailed estates in the Ancien Régime.
