Over the centuries the concrete form in which the Church has exercised this power received from the Lord has varied considerably. During the first centuries the reconciliation of Christians who had committed particularly grave sins after their Baptism (for example, idolatry, murder, or adultery) was tied to a very rigorous discipline, according to which penitents had to do public penance for their sins, often for years, before receiving reconciliation. To this “order of penitents” (which concerned only certain grave sins), one was only rarely admitted and in certain regions only once in a lifetime. During the seventh century Irish missionaries, inspired by the Eastern monastic tradition, took to continental Europe the “private” practice of penance, which does not require public and prolonged completion of penitential works before reconciliation with the Church. From that time on, the sacrament has been performed in secret between penitent and priest. This new practice envisioned the possibility of repetition and so opened the way to a regular frequenting of this sacrament. It allowed the forgiveness of grave sins and venial sins to be integrated into one sacramental celebration. In its main lines this is the form of penance that the Church has practiced down to our day.
Catechism of the Catholic Church Paragraph 1447].
Most people fall into grave sin more than once in a life time. What of those people in those regions which only permitted the sacrament once? As well, it seems that this very strict manifestation of the sacrament was only exercised in cases of very grave sins such as murder, abortion or adultery. What of other more common and more minor sins that still can constitute grave matter (ex. lustful thoughts, etc). Does anyone know how the Church dealt with such matters during these early centuries?