Her original name was Teresa de Cepeda y Ahumada, and her chosen name as a nun was Theresa of Jesus. She came of a well-to-do noble family. She entered the Carmelite order (possibly in 1536). Much later she underwent (c.1555) a "second conversion," after which she experienced mystic visions. She had entertained a desire to found a house of reformed Carmelites (the Discalced, or Barefoot, Carmelites, living in strict observance of the rule) long before she had the opportunity in 1562 to found the Convent of St. Joseph in Ávila. Other foundations were made, and in the busy years that followed she traveled much to the various houses. She also founded convents of friars, having as her collaborator another great mystic, St. John of the Cross.
St. Theresa combined intense practicality with the most rarefied spirituality. She was an excellent and tireless manager, waging a long and ultimately successful struggle with other branches of the clergy to have the Discalced Carmelites separated from the older order and eventually founding 17 convents. The reawakening of religious fervor that she brought about in Spain was astonishing. Soon after her death the movement spread beyond Spain and across Christendom, having a profound effect on the Counter Reformation. She brought mysticism and its fruits to the common person. She was canonized in 1622. Feast: Oct. 15.