Saint Teresa of Ávila, also called Saint Teresa of Jesus, baptized as Teresa Sánchez de Cepeda y Ahumada (28 March 1515 – 4 October 1582), was a prominent Spanish mystic , Roman Catholic saint , Carmelite nun and author during the Counter Reformation , and theologian of contemplative life through mental prayer . She was a reformer in the Carmelite Order of her time and the movement she initiated, later joined by Saint John of the Cross , eventually led to the establishment of the Discalced Carmelites , though neither she nor John were alive when the two orders separated. In 1622, forty years after her death, she was canonized by Pope Gregory XV , and on 27 September 1970 was named a Doctor of the Church by Pope Paul VI . [5] Her books, which include her autobiography ( The Life of Teresa of Jesus ) and her seminal work El Castillo Interior (trans.: The Interior Castle ), are an integral part of Spanish Renaissance literature as well as Christian mys