teresa of ávila, also called saint teresa of jesus, baptized as teresa sánchez de cepeda y ahumada, (march 28, 1515 – october 4, 1582) was a well known spanish mystic, roman catholic saint, carmelite nun, writer of the counter reformation, and theologian of contemplative life through mental prayer. she was a reformer of the carmelite order and is considered to be a founder of the discalced carmelites along with john of the cross.