Augustinian nuns are the most ancient and continuous segment of the Roman Catholic Augustinian religious order under the canons of contemporary historical method. The Augustinian nuns, named after Saint Augustine of Hippo (died AD 430), are several Roman Catholic enclosed monastic orders of women living according to a guide to religious life known as the Rule of St. Augustine. Prominent Augustinian nuns include Italian composer Vittoria Aleotti, Italian mystic St. Clare of Montefalco, German mystic Anne Catherine Emmerich and St. Rita of Cascia.
Though Augustine of Hippo probably didn't compose a formal monastic rule (despite the extant Augustinian Rule), his hortatory letter to the nuns at Hippo Regius (Epist., ccxi, Benedictine ed.) is the most ancient example on which the beginnings of this Augustinian Rule are based.
The nuns regard as their first foundation the monastery for which St. Augustine wrote the rules of life in his Epistola ccxi (alias cix) in 423. It is certain that this epistle was called the Rule of St. Augustine for nuns at an early date, and has been followed as the rule of life in many female monasteries since the 11th century. These monasteries were not consolidated in 1256, like the religious communities of Augustinian monks.
Each convent was independent and was not subject to the general of the order. This led to differences in rule, dress, and mode of life. Only since the 15th century have certain Augustinian Hermits reformed a number of Augustinian nunneries, become their spiritual directors, and induced them to adopt the Constitution of their order. Henceforth, there were female members of the Order of Hermits of St. Augustine in Italy, France, Spain, Belgium and later in Germany, where, however, many were suppressed during the Reformation, or by the secularizing law of 1803. In the other countries many nunneries were closed in consequence of the French Revolution. The still existing houses in the early 20th century, except Cascia, Renteria (Diocese of Vitoria), Eibar (Diocese of Vittoria) and Cracow, were under the jurisdiction of the bishop of the diocese. Many convents are celebrated for the saints whom they produced, such as Montefalco in Central Italy, the home of St. Clare of the Cross (or St. Clara of Montefalco, d. 1308), and Cascia, near Perugia, where St. Rita died in 1457. In the suppressed German convent of Agnetenberg near Dulmen, in Westphalia, lived Anne Catherine Emmerich celebrated for her visions.
Mention should also be made of the monastery of the so-called Augustinians delle Vergini, at Venice, founded in 1177 by pope Alexander III after his reconciliation with Holy Roma Emperor Frederick Barbarossa, whose daughter Julia, with twelve girls of noble birth, entered the monastery and became first abbess. Doge Sebastiano Zani, who had endowed the institution, was appointed patron, with the privilege of approving the election of the abbess before the granting of the papal confirmation. On the French occupation in the 18th century the religious went to America, where they devoted themselves to the work of teaching and the care of the sick. Later they established monasteries in Italy and in 1817 in Paris. Towards the end of the 16th century communities of female Discalced Augustinians appeared in Spain. The first convent, that of the Visitation, was founded at Madrid, in 1589, by Prudencia Grillo, a lady of noble birth, and received its Constitution from Father Alfonso of Orozco. Juan de Ribera, Archbishop of Valencia (d. 1611), founded a second Discalced Augustinian congregation at Alcoy, in 1597. It soon had houses in different parts of Spain, and in 1663 was established at Lisbon by Queen Louise of Portugal. In addition to the Rule of St. Augustine these religious observed the exercises of the Reformed Carmelites of St. Teresa. In the convent at Cybar, Mariana Manzanedo of St. Joseph instituted a reform which led to the establishment of a third, that of the female Augustinian Recollects. The statutes, drawn up by Father Antinólez, and later confirmed by Paul V, bound the sisters to the strictest interpretation of the rules of poverty and obedience, and a rigorous penitential discipline. All three reforms spread in Spain and Portugal, but not in other countries.
A congregation of Augustinian nuns under the title "Sisters of St. Ignatius" was introduced into the Philippines and South America by the Discalced Augustinian Hermits. They worked zealously in aid of the missions, schools and orphanages in the island, and founded the colleges of Our Lady of Consolation and of St. Anne at Manila, and houses at Neuva Segovia, Cebú and Mandaloya on the Pasig, where they have done much for the education of girls.
Historically, the most important of the observant Augustinian congregations were the Spanish Augustinian tertiary nuns, founded in 1545 by Archbishop Thomas of Villanova at Valencia; the "reformed" Augustinian nuns who originated under the influence of Augustinian educated Carmelite St Theresa after the end of the 16th century at Madrid, Alcoy, and those founded in Portugal.
The Augustinian Ethos 
The teaching and writing of Augustine, the Augustinian Rule, and the lives and experiences of Augustinians over 16th centuries help define the ethos of the order, sometimes "honoured in the breach".
As well as telling his disciples to be "of one mind and heart on the way towards God" Augustine of Hippo taught that "Nothing conquers except truth and the victory of truth is love" (Victoria veritatis est caritas), and the pursuit of truth through learning is key to the Augustinian ethos, balanced by the injunction to behave with love towards one another. It does not unduly single out the exceptional, especially favour the gifted, nor exclude the poor or marginalised. Love is not earned through human merit, but received and given freely by God's free gift of grace, totally undeserved yet generously given. These same imperatives of affection and fairness have driven the order in its international missionary outreach. This balanced pursuit of love and learning has energised the various branches of the order into building communities founded on mutual affection and intellectual advancement. The Augustinian ideal is inclusive.
Augustine spoke passionately of God's "beauty so ancient and so new", and his fascination with beauty extended to music. He taught that "to sing once is to pray twice" (Qui cantat, bis orat), and music is also a key part of the Augustinian ethos. Besides the significant musical contribution of Augustinian nun and composer Vittoria Aleotti, contemporary Augustinian musical foundations include the famous Augustinerkirche of the (male) friars in Vienna where orchestral Masses by Mozart and Schubert are performed every week, as well as the boys' choir at Sankt Florian in Austria, a school conducted by Canons Regular, a choir now over 1,000 years old.
Augustinian Congregations 
Other orders and groups of women that are not enclosed and belong within the Augustinian family either because they follow the Rule of Augustine or have been formally aggregated through their constitutions into the worldwide Augustinian Order are: The Sisters of St Rita, The Augustinian Sisters of Mercy of Jesus (South Africa), the Augustinian Recollects and the Sisters of Our Lady of Consolation (both in the Philippines), the Congregation of Our Lady of the Missions, the Sisters of Charity of the Incarnate Word (who established the University of the Incarnate Word in Texas), and the Sisters of St Joan of Arc (in Quebec, United States, and Rome) are just some of the Augustinian family of orders who are not enclosed women. The Sisters of Life are a relatively new order (founded 1991 by Cardinal O'Connor) who follow the Augustinian rule.
There are other Augustinian nuns in the Anglican Communion.
Women leaders and Saints who followed the Augustinian Rule 
- Reformer St. Juliana of Mt. Cornillon (1193–1258)
- Italian mystic Clare of Montefalco (c. 1268 – 18 August 1318)
- Mother and mystic St Rita (1381–1457)
- Composer Vittoria Aleotti (c.1575–after 1620)
- Abbess Blessed Maria Teresa Fasce
- Mother and nun Blessed Helen of Udine
See also 
- Augustinian nuns in the Anglican Communion
- Order of Augustinian Recollects
- The Dominicans
- Independent Augustinian Communities
- Catholic Encyclopaedia article – now very outdated
- Augustine of Hippo The Rule of St Augustine Constitutiones Ordinis Fratrum S. Augustini (Rome 1968)
- Augustine of Hippo The Rule of St Augustine Constitutiones Ordinis Fratrum S. Augustini (Rome 1968) Chapter I
- Augustine of Hippo Sermons 358,1 "Victoria veritatis est caritas"
- Augustine of Hippo Confessions 10, 27
- Augustine of Hippo Sermons 336, 1 PL 38, 1472
- c.f. The Rule of Saint Augustine and the Constitutions of the Order of the Incarnate Word and Blessed Sacrament New York: Schwartz, Kirwin, and Fauss, 1893, pp. 33–35.
- Bibliography for the Augustinian official website
- Augustine of Hippo, The Rule of St Augustine Constitutiones Ordinis Fratrum S. Augustini (Rome 1968)
- The Augustinians (1244–1994): Our History in Pictures. Pubblicazioni Agostiniane, Via Paolo VI, 25, Roma, Italy.
- Canning O.S.A, Rev. R. (1984). The Rule of St Augustine. Darton, Longman and Todd.
- Orbis Augustinianus sive conventuum O. Erem. S. A. chorographica et topographica descriptio Augustino Lubin, Paris, 1659, 1671, 1672.
- Regle de S. Augustin pour lei religieuses de son .ordre; et Constitutions de la Congregation des Religieuses du Verbe-Incarne et du Saint-Sacrament (Lyon: Chez Pierre Guillimin, 1662), pp. 28–29. Cf. later edition published at Lyon (Chez Briday, Libraire,1962), pp. 22–24. English edition, The Rule of Saint Augustine and the Constitutions of the Order of the Incarnate Word and Blessed Sacrament (New York: Schwartz, Kirwin, and Fauss, 1893), pp. 33–35.
- Zumkeller O.S.A.,Adolar (1986). Augustine's ideal of Religious life. Fordham University Press, New York.
- Zumkeller O.S.A.,Adolar (1987). Augustine's Rule. Augustinian Press, Villanova, Pennsylvania U.S.A.
- International Order of St. Augustine
- October 2009+02:14:53 Text of the Rule of St. Augustine
- Catholic Encyclopedia entry for "Canons and Canonesses Regular"
- Augustinian nuns (America)
- Augustinian nuns at Santo Quattro, Rome, Italy
- Augustinian nuns at Cascia, Italy
- The historic priory of Grace Dieu (England)
- List of Augustinian Saints
- Augustinian Missionary Sisters
- Order of the Hermit Friars of St. Augustine (O.S.A.)
- Society of Saint Augustine (S.S.A.)