Mechtilde or Matilda was born in 1241 or 1242 in Hackeborn, as a countess. She became a nun in the Benedictine convent of Helfta.
"She was distinguished by her humility, her fervor, her friendliness, the clarity and the innocence of her life and by the familiarity and intensity with which she lived her relationship with God, the Virgin and the Saints."
Divine praise was the keynote of her life as it is of her book, The Book of Special Grace. She wrote commentaries of liturgical texts, particularly of the Ave Maria prayer.
The angels lead Mechtilde to Mary, reminding her of her joys.
Mechtilde praised Mary more than she would implore her. She liked to contemplate her glory more than her sorrows. Mary is the model of the soul because of the richness of her virtues. 
Here is a prayer she composed, quoted by Benedict XVI in the general audience of September 29, 2010:
"I greet you, O most deeply venerated Virgin, in that sweetest of dews which from the Heart of the Blessed Trinity spread within you; I greet you in the glory and joy in which you now rejoice for ever, you who were chosen in preference to all the creatures of the earth and of Heaven even before the world's creation! Amen."
 Benedict XVI, General Audience of September 29, 2010
 Dom J. Leclercq, Dévotion et théologie mariales dans le monachisme bénédictin (Marian Devotion and Theology in Benedictine Monasticism), in Hubert du Manoir, Maria, Volume 2, Beauchêne Paris 1952, p. 563
 Mechtilde, Liber specialis gratiae, The Book of the Special Grace, I, 45