St Teresa of Avila

Born in Avila, Spain, on March 28th, 1515, St. Teresa was the daughter of a Toledo merchant and his second wife, who died when Teresa was 15, one of ten children. Shortly after this event, Teresa was entrusted to the care of the Augustinian nuns. After reading the letters of St. Jerome, Teresa resolved to enter a religious life. In 1535, she joined the Carmelite Order. She spent a number of relatively average years in the convent, punctuated by a severe illness that left her legs paralyzed for three years, but then experienced a vision of "the sorely wounded Christ" that changed her life forever.

"The Ecstasy of St Teresa" by Bernini

From this point forward, Teresa moved into a period of increasingly ecstatic experiences in which she came to focus more and more sharply on Christ's passion. With these visions as her impetus, she set herself to the reformation of her order, beginning with her attempt to master herself and her adherence to the rule. Gathering a group of supporters, Teresa endeavored to create a more primitive type of Carmelite. From 1560 until her death, Teresa struggled to establish and broaden the movement of Discalced or shoeless Carmelites. During the mid-1560s, she wrote the Way of Perfection and the Meditations on the Canticle. 
In 1567, she met St. John of the Cross, who she enlisted to extend her reform into the male side of the Carmelite Order. Teresa died in 1582, and she left to posterity many new convents, which she continued founding up to the year of her death. She also left a significant legacy of writings, which represent important benchmarks in the history of Christian mysticism. These works include the Way of Perfection and the Interior Castle. She also left an autobiography, the Life of Teresa of Avila.
This is one of St Teresa's famous quotes:
“Let nothing disturb you; Let nothing dismay you;
All things pass: God never changes.
Patience attains all that it strives for.
He who has God lacks for nothing:
God alone suffices.”