The execution of the choir stalls is dated to the last part of the fifteenth century (1493-1498 are the most common estimates),during the period in which Don Pablo Martinez de Urunuela was the abbot. We are not sure of the author, but the work has been attributed to the Amutio brothers, Jews from the village of Cardenas; there are a number of Jewish symbols on the carvings.The sixty-eight stalls, forty-one on the upper level and twenty-seven on the lower level are arranged on three sides of the choir loft,overlooking the nave; they form a "U" structure.