The Rule of St. Benedict

Whoever is excommunicated for graver faults from the oratory and the table, let him, at the time that the Work of God is celebrated in the oratory, lie stretched, face down in silence before the door of the oratory at the feet of all who pass out. And let him do this until the Abbot judgeth that it is enough. When he then cometh at the Abbot's bidding, let him cast himself at the Abbot's feet, then at the feet of all, that they may pray for him. If then the Abbot ordereth it, let him be received back into the choir in the place which the Abbot shall direct; yet so that he doth not presume to intone a psalm or a lesson or anything else in the oratory, unless the Abbot again biddeth him to do so. Then, at all the Hours, when the Work of God is ended, let him cast himself on the ground in the place where he standeth, and thus let him make satisfaction, until the Abbot again biddeth him finally to cease from this penance.

But let those who are excommunicated for lighter faults from the table only make satisfaction in the oratory, as long as the Abbot commandeth, and let them perform this until he giveth his blessing and saith, "It is enough."