This research deals with the different uses that had the old Trinitarian convent of San Onofre. They reuse as infantry barracks from 1852 until well into the twentieth century as headquarters of the Guardia Civil has resulted in multiple transformations. Through its interventions can make a reading of the property, as well as the materials used and the solutions given to the problems of adaptation to improper use. The study methodology is based on document analysis preserved in the Military Historical Archive of Segovia. The aim is to publicize the intervention processes and adaptation of a religious space in military and later in culture, although the latter unfinished