Francisco de Osuna was a Spanish author, born in Seville.

His book The Third Spiritual Alphabet influenced Saint Teresa of Avila

Teresa of Ávila

Saint Teresa of Ávila, also called Saint Teresa of Jesus, baptized as Teresa Sánchez de Cepeda y Ahumada, was a prominent Spanish mystic, Roman Catholic saint, Carmelite nun, and writer of the Counter Reformation, and theologian of contemplative life through mental prayer...

. The book is considered a masterpiece of Franciscan

Franciscan

Most Franciscans are members of Roman Catholic religious orders founded by Saint Francis of Assisi. Besides Roman Catholic communities, there are also Old Catholic, Anglican, Lutheran, ecumenical and Non-denominational Franciscan communities....

mysticism. His premise in the book is that friendship and communion with God are possible in this life through cleansing one's conscience, entering one's heart, resting in loving stillness, and then rising above the heart to God alone.

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