In 1569, Charles Borromeo started archconfraternities in Milan as a way to standardize the practice of the various penitent confraternities.
[1] Canonical erection is the approval of the proper ecclesiastical authority which gives the organization a legal existence.
In the case, however, of many confraternities and archconfraternities, the power of erection is vested in the heads of certain religious orders.
[2] Aggregation, or affiliation, as it is also called, may be made by those only who have received from the Holy See express powers for that purpose.
The bishop must approve, but may modify the practices and regulations of the confraternity to be aggregated, except those to which the indulgences have been expressly attached.