The Most Ancient Lives of Saint Patrick/The Life and Acts of St. Patrick/Chapter 194
The Miraculous Rising of the Sea between the Contending People.
And at the sight of such a miracle, the people could not be restrained from their contention, for the fury of their wrath and the violence of their minds which governed them they imputed to their devotion toward the saint. And on the twelfth day a deadly and perilous contention arose between the two people of Ulydia and Ardmachia about the sacred body. And while arrayed in armor they rose unto arms, they heard a voice from heaven, which seemed as the voice of Saint Patrick, staying their violence; and the sea, rising above its wonted bounds, reared itself as a wall, and separated the contending people, so that they could neither behold nor attack one the other; and thus corporeally separated, united them unto the concord of mutual peace. Then the people being restrained from their fury, the waters surceased from their fury also.