After this the same king Dímma required a small gift from Saint Fintán, and Fintán gave him his flaxen tunic, in which Fintán has slept for one night, and said to the king:
‘Watch over this tunic diligently for there will come a day when this tunic will be of use to you and will deliver you from great danger’.
After this the aforesaid Cellach son of Dímma became a brigand and slew Áed Sláne, son of Crundmáel, king of the Leinstermen. Then Crundmáel, having gathered an army of all the Leinstermen, came and beset the Fotharta in Inis Barri on Loch Edidach. But Dímma Camchoss got away from the island on his horse, and he got away past the multitude of all the Leinstermen, and no one saw him because Fintán's tunic concealed him. But his familia, namely eighty men of the nobles of the Fotharta, were held in captivity on the isle of Tobairri, and every day two men from among them were slain, and Cellach son of Dímma was slain. And Dímma mac Áeda Croin, Fintán's friend, was held captive with them. Then Fintán said to his company:
‘Arise, let us go, for the man who has offered us this locus is held in captivity [and] is to be slain tomorrow’.
Then Fintán, having taken twelve men with him, came to the kings' camp. When the kings had seen the chariot and the clerics from far off, they knew that it was Fintán, and that he had come to free Dímma mac Áeda Croin. Then Crundmáel said:
‘Take the man and hide him, and slay him before Fintán arrives, and meanwhile celebrate as though he had [already] been slain’.
Hearing the celebration, Fintán said:
‘What is that song’?
Someone replied to him:
‘This is a celebration following the slaying of a man’.
Fintán said:
‘I have not heard this voice before today. From this day, the kings of this people—except Crundmáel and another man after him—will never ever hold the kingship longer than seven years’.
Crundmáel was summoned to Fintán, who said to him:
‘Release to us Dímma, who is held captive by you’.
‘He has been slain’.
And Fintán said:
‘This cannot be, for that man will never be slain’.
Indeed the men who have been sent to slay him were not able to raise their hands, neither swords nor spears could wound him. Hearing this, Crundmáel offered that man along with his [own] inheritance and offspring to Saint Fintán forever.