Seven months after this great happiness, St. Monica died asking her son to "remember her at the altar of God". Augustine, becoming a priest, offered the Holy Sacrifice for her. "Lord," he often said, "have mercy on my mother; she was good, she pardoned easily, pardon her also her sins."
Made bishop of Hippo, at the age of 41 (Alleluia, Communion), he began from that moment to live canonically, that is to say, in common with his clerks. [The word canon, canonicus, derived from Kanon, in the sense of clerks attached to a church with a stipend for their subsistence. To live canonically was to live in common. Later on it meant to lead a regular life, under a rule.] This community gave bishops and priests to many churches, and thus the institute of St. Augustine spread little by little in Africa and more specially in Gaul. The rule of St. Augustine, which makes him one of the four great founders of religious orders, is drawn from the 211th epistle which he wrote for nuns and which later on was adapted for men.
[The best known Augustinian Orders are: the Canons Regular of St. Augustine and the Hermits of St. Augustine. The Canons founded many Congregations: that of Windeshem, with the mystic writers John Ruysbroeck and Thomas a Kempis; the Lateran Congregation which has monasteries in England, France, BelgIum and America. The Hermits have now in Europe, Mexico and the Philippine Islands, more than 60 monasteries, 280 mission stations, with more than 2000 members. - date c. 1950]
Owing to the sublimity of his knowledge and the ardour of his love this saint was also one of the four great doctors of the West.
He died in A.D 430, after an episcopate of 36 years, reciting the Penitential Psalms.
In medio Ecclesiae aperuit os ejus: et implevit eum Dominus spiritu sapientiae et intellectus: stolam gloriae induit eum. * Bonum est confiteri Domino: et psallere nomini tuo, Altissime.
In the midst of the Church the Lord opened his mouth: and He filled him with the spirit of wisdom and understanding: He clothed him with a robe of glory. * It is good to give praise to the Lord: and to sing to Thy name, O most High.
(Ecclesiasticus 15:5 and Psalm 91:2 from the Introit of Mass)
Adesto supplicationibus nostris, omnipotens Deus: et quibus fiduciam sperandae pietatis indulges, intercedente beato Augustino, Confessore tuo atque Pontifice, consuetae misericordiae tribue benignus effectum.
O almighty God, attend to our supplications, and by the intercession of blessed Augustine, Thy confessor and bishop, graciously grant the effect of Thy wonted mercy to those, to whom Thou givest firm trust in Thy loving kindness for which we hope.
From the Catholic Encyclopaedia: http://www.newadvent.org/cathen/02084a.htm