This section is from the book "Ancient Legends, Mystic Charms, And Superstitions Of Ireland", by Jane Francesca Wilde. Also available from Amazon: Ancient Legends, Mystic Charms, And Superstitions Of Ireland.
In the old churchyard of the monastery at Saints' Island, there is also an ancient black marble flagstone; and the monks gave it power as A Revealcr of Truth, and it is called the Cremave, or Swearing Stone.
Any one suspected of sin or crime is brought here from the country round, and if the accused swears falsely, the stone has the power to set a mark upon him and his race for seven generations. But if no mark appears then he is known to be innocent ; and as long as the world lasts, the stone is to have this power, for so the monks decreed ; and with many holy and mystic ceremonies they gave it consecration, as the " Revealer of Truth." And though the English burned the monastery and defaced the altar and carried off the holy vessels, yet they had no power over the Cremave, or Swearing Stone, which remains to this day.
Many years ago, so runs the tale, a murder was committed in the neighbourhood, and a certain man being suspected as the murderer, he was forced to go to the " clearing stone " ; for the people said, " If he is innocent, the
Cremave will clear him ; and if guilty, let him suffer for his crime."
So, on the appointed day, he went with his friends and the accuser to the Swearing Stone ; and there he was met by the priest, who adjured him to speak the truth in presence of all the people and before the face of God.
The man laid his hand upon the stone, and solemnly swore that he was innocent ; but instantly his right arm was shrivelled up, his feet failed, and he was carried home a miserable cripple, and so remained to the end of his life.
Some weeks after, a daughter was born to him, who bore across her forehead the impress of a bloody hand; and every one of his descendants have some strange mark, by which the people know that the race is accursed to the seventh generation ; after which time the doom will be lifted, and the expiation made for the crime and the perjury will be considered sufficient by the Lord in heaven, who will then grant to the race pardon and grace at last.