St. Teresa lived in the 16th century during the protestant reformation. She grew up with a strict father who sent her to the convent to combat her constant rebellion. There she first formed a relationship with Jesus and eventually decided to become a professed sister because she feared of her sinfulness if she returned to the world. At the time, her convent focused more on prestige than piety, and St. Teresa was attracted to this lifestyle. She found herself with little to no prayer life throughout her 30s. After exhortation from a priest and suffering extreme illness, Teresa returned to mental prayer and eventually started receiving visions. From these we have many writings of St. Theresa including Interior Castle.

Realizing the corruption of her convent, Teresa desired to reform the order and start her own convent. After much ridicule, she was able to do so and began a simple life focused on prayer, love, and the joy of God. Even through persecution, many young women joined her and she formed the Discalced Carmelites. She tried to bring her order wherever it was welcome. St. Teresa died of illness at the age of 67. She is one of the four female Doctors of the Church and is the patron saint of those who suffer headaches.