The genesis of the documents during the chancellery of Alfonso X.

The Chancellery of Alfonso X represents one of the most signi-ficant milestones for the study of the configuration of the future Spanish Administration. One of the least known subjects of his reign is the pro-cess followed to draft his documents —the genesis of the documents—. Having disappeared the records of the Castilian Chancellery, the use of the legal sources of Alfonso X like: Speculum, Fuero Real, Partidas and the Monarch´s documents have become essential to develop this work. This work approaches the different stages of construction of the docu-ment, from its “actio” to its “conscriptio” which we have divided into “documental” and “cancilleresca”, respectively. This division is due to, on one hand, to the different places in which documents were created and on the other hand, to the strengthening of the belief that the Chan-cellery was the place where the documents were validated and can-celled.