Teresa of Avila was a Spanish mystic and reformer born on March 28, 1515. She is best known for her role in the Carmelite Order, where she established the Discalced Carmelites, a reformed branch that emphasized a more contemplative and austere lifestyle. Teresa's writings on prayer and spirituality, including her famous work, "The Interior Castle," have had a lasting impact on Christian mysticism. In 1970, Pope Paul VI declared Teresa a Doctor of the Church, recognizing her significant contributions to theology and spirituality. She is also the patron saint of Spain and is celebrated for her deep commitment to prayer and her efforts to promote a more profound spiritual life among Christians.