In the course of the Gregorian reforms of the 11th century in which Pope Gregory VII attempted to return Christendom to the purity of the church of the Apostles, steps were taken to mould the Canons Regular community in a more monastic form (the common life with renunciation of private property, chastity, obedience, the liturgical life and the care of souls: to these can be added two other characteristics typically Augustinian—a close bond of brotherly affection and a wise moderation in all things).
To this purpose, at the great Lateran Council of 1059 the Augustinian Rule was prescribed while the Aachen Rule for Canons which permitted the ownership of private property was firmly denounced. Cardinal Hildebrand of Sovana, later to become Pope Gregory VII (1073-1085), played an important role during the Council. The Reform was carried through by degrees and was not adopted by all canonical monasteries. This explains why there is a difference between religious clerics, Canons Regular living according to the Rule of St. Augustin in community without personal possessions (‘Canonici Regulares’), and secular clerics (‘Canonici Irregulares’) living according to the Aachen Rule for Canons living in separate households and owning personal property.
In addition to the reform of existing monasteries there was an upsurge in monastic foundations, especially in German-speaking Europe and the mid 11th to the mid 12th century can be referred to as the century of Canons Regular.