The Most Ancient Lives of Saint Patrick/The Life and Acts of St. Patrick/Chapter 74
Of the Saint's Prophecy concerning the Kings of Momonia.
And the saint, going out of Lagenia, journeyed prosperously forward into the country of Momonia. And the king thereof, who was named Oengus, met the holy prelate, rejoicing and giving thanks in the exultation of his heart, as on that day occasion was ministered unto him of joy and of belief, for that in the morning, when he entered the temple to adore his idols, he beheld them all prostrate on the ground. And so often as he raised them, so often by the divine power were they cast down; nor could they stand upright, but continually were they overthrown. And as Dagon could not stand at the approach of the ark of the testament, so neither could the idols stand at the approach of Saint Patrick. And he may truly be called the ark of the covenant, who in his pure heart, as in a golden urn, bore the manna of heavenly contemplation, the tables of the heavenly law, and the rod of the heavenly discipline. And the king brought him, with great reverence and honor, unto his palace in the city of Cassel, because his mind and his eye had long time longed for him, by reason of the manifold miracles which he knew had been worked by the saint. And at his preaching the king believed in the Holy Trinity, in the name of which he is regenerated in the healing water of baptism. And after he had blessed the king by touching his head, at his earnest and devout entreaty the saint pierced his foot with the point of the staff of Jesus. But the king, receiving his blessing with ardent desire, felt in his body no pain of the wound, so much did he rejoice in the salvation of his soul. Then did the saint behold the wounded foot of the king, and imprinted on it the sign of the cross, and blessed it, and healed the wound; and, full of the prophetic spirit, thus prophesied he unto the king: "The blood of any king of thy race who shall sit on thy throne shall never be shed, save of one alone." And the inhabitants of this region, assert the prophecy to have been proved by undeniable truth, inasmuch as history recordeth not one king of all his posterity, even to the tenth generation, to have been slain, but only one. And there remained in that place a tablet of stone, whereon the saint is said to have celebrated the holy mysteries; and it is called by the Irish Leac Phadruig—that is, the Stone of Saint Patrick; and on this stone, for reverence of him, the kings of Cassel are wont to be crowned and to be advanced unto the throne of their kingdom.