The Penitential of Cummean (Trans. Oliver Davies, in Celtic Spirituality [New York, 1999])
8.14. If anyone injures the good name of a brother whom he loves through idle gossip, he shall do penance in silence for one or two days.
8.15. But if he did it in conversation, he shall sing twelve Psalms.
9.13. Those who show barbarians the way shall do penance for fourteen years, provided there is no massacre of Christians. But if there is, they shall give up their weapons and shall live for God until they die, being dead to the world.
9.14. He who despoils monasteries, falsely saying that he is redeeming captives, shall go for one year on bread and water, and everything that he has taken he shall give to the poor, and he shall do penance for two years without wine and meat.
Last comments in Cummean’s commentary:
But this is to be carefully observed in all penance: the length of time anyone remains in his faults, what education he has received, with what passion he is assailed, with what courage he resists, with what intensity of weeping he seems to be afflicted, with what pressure he is driven to sin. For Almighty God, who knows the hearts of all and has made us all different, will not weigh the burden of sins on an equal scale of penance, as this prophecy says: “For dill is not threshed with a threshing sledge, nor is a cart wheel rolled over cummin; but dill is beaten out with a stick and the cummin with a rod, but bread corn shall be broken small (Is. 28:27-28), or as in this passage: “The mighty shall be mightily tormented” (Wis. 6:7).
Columba / Columcille (521-597)
Gregory the Great (540-604)
Augustine of Canterbury (died 604-5)
Paulinus (d. 644)
The Venerable Bede (672/3-735):
The Ecclesiastical History of the English People
Eanfled also, the queen, with her train observed after the same manner as she had seen it practiced in Kent, having with her a priest of Catholic observation out of Kent, by name Romanus: whereby, as it is said, it happened sometimes in those days that in one year Easter was kept twice, and when the king [Oswy] was breaking his fast and solemnizing the Lord’s Easter, then the queen and her company continued yet the fast and kept the day of palms.
Muhammad (c. 570-632)