Commentaries and transcription of 32 documents of the Castellán de Amposta Sancho de Aragón, conserved in the Archivo Histórico Nacional de Madrid, the series « Registros de Actas Capitulares de la Asamblea de la Castellanía de Amposta « (name that the Priorato de Aragón receives, of the Order of the Hospital of San Juan de Jerusalem). This documentation, dated between 1339 and 1341, little has been studied, partly by to have waked up more interest the period immediately later, corresponding to the well-known fry Juan Fernández de Heredia