St. Teresa, also known as Saint Teresa of Ávila, was a prominent Spanish mystic and reformer of the Carmelite Order in the 16th century. Born on March 28, 1515, she is known for her deep spiritual writings and her role in the Catholic Church's Counter-Reformation. Her most famous works include "The Interior Castle" and "The Way of Perfection," which explore themes of prayer and spiritual growth. In 1970, she was canonized by Pope Paul VI and declared a Doctor of the Church, making her one of the first women to receive this honor. St. Teresa's legacy continues to influence Christian spirituality and mysticism today.