Teresa of León was a prominent Spanish mystic and religious reformer born in 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 austere and contemplative lifestyle. Her writings on prayer and spirituality have had a lasting impact on Christian mysticism. In 1970, Teresa of León was canonized as a saint by the Catholic Church and declared a Doctor of the Church in 1970, making her one of the first women to receive this honor. Her feast day is celebrated on October 15, and she is recognized for her deep commitment to faith and reform within the church.