St. Teresa was born in Avila, Spain in 1515. She was the daughter of a business trader and his second wife. Her father died when Teresa was 15, being one of ten children. Shortly after this, Teresa was giving over to the care of a group of Augustinian nuns. After reading some of St. Jerome's works she resolved to enter a Religious order. In 1535, she joined the Carmelites. She lived in the convent, but often had severe illnesses that left her legs paralyzed for three years. However during this time she experienced a life changing vision of "the sorely wounded Christ."

From this point on, Teresa moved into a period of increasingly other-worldly experiences in which she came to focus more and more sharply on the passion of Christ. From these visions she set about reforming her order starting with mastering herself and following the rule. With a devoted group of supports Teresa tried to create a stricter form of the Carmelite order, known as discalced or shoeless Carmelites. During this time she wrote the Way of Perfection and the Meditations on the Song of Solomon. In 1567, she met with St. John of the Cross, who she encouraged to reform the male side of the Carmelite Order. Teresa died in 1582.