Teresa de Cepeda y Ahumada was born on March 28, 1515 in Avila, Spain. She was of Jewish descent and her family was quite well-off despite having had trouble with the Inquisition a few generations earlier.
From a young age, Teresa was extremely devoted to God and displayed some rather unusual behavior. When she was seven years old, she and her little brother ran away in the hopes of becoming martyrs by sacrificing themselves to the Moors. Thankfully, their uncle caught them before they got very far.
Teresa was only 14 when her mother died. Her father placed her in a convent school but illness forced her to be removed a year later. After returning home, she told her father she wanted to be a nun. Although he told her she would have to wait until he was dead, she ran away to the Carmelite convent of the Incarnation during the year 1535.
While in the convent, Teresa’s illness worsened. It is now thought that she was suffering from malaria. Prayer was the only thing that helped her and she was miraculously healed in 1539.
During the 16th century, the Carmelite order and, most particularly, the convent of the Incarnation had become extremely lax in its observance. Teresa herself developed several bad habits. Years later, the council of a priest made her aware of the state of her soul.
Teresa returned to a life of contemplation. She set out to reform her order and spent several years in total seclusion while awaiting the permission of her superiors. During the 1550s, Teresa began showing signs of deep mysticism including levitation and pain inflicted by her supernatural visions. Several people who did not approve of her reforms suggested that her gifts were diabolical. However, even during her lifetime, no one could find anything spiritually wrong with Teresa.
Teresa reformed seven convents and, with the help of Saint John of the Cross, at least two monasteries for men. In 1576, the jealously of her fellow Carmelites forced her to retire to Toledo. During the early 1580s, however, she was allowed to leave and she founded 17 more convents. She and John of the Cross are now considered the founders of the Discalced Carmelites.
While she was in Toledo, Teresa wrote her most famous work: El Castillo Interior or The Interior Castle. This, coupled with her earlier work The Way of Perfection, is considered one of the world’s greatest works on the contemplative life.
Teresa of Avila suffered from very bad health during the last part of her life. She died on October 15, 1582 at the age of 65.
Saint Teresa of Avila was canonized by Pope Gregory XV on March 12, 1622. She was declared a Doctor of the Church by Pope Paul VI in 1970. Saint Teresa is the patron saint of people ridiculed for their piety and is often invoked to prevent headaches. Her feast day is October 15.
Source: Butler’s Lives of the Saints