In ancient Pagan times in Ireland the poets were supposed to possess
the gift of prophecy, and by certain means could throw themselves into
a state in which they had lucid vision of coming events. This state,
called _Imbas for Osna_, was produced by incantations and the offering
of the flesh of a red pig, a dog, or a cat to their idols. Then the
poet, laying the two palms of his hands on his two cheeks, lay down
and slept; his idol gods being beside him. And when he awoke he could
see all things and foretell all things. He could make verses with the
ends of his fingers, and repeat the same without studying, and in this
way proved his right to be chief poet at the court of the king. Also
he laid his staff upon the head of a person, and thus he found out his
name, and the name of his father and mother, and all unknown things
that were proposed to him. And this prophetic power was also obtained
by _Imbas for Osna_, though a different kind of offering was made to
the idol.
But Patrick abolished these practices, and declared that whoever used
them should enjoy neither heaven nor earth; and he substituted for
them the _Corus Cerda_ (the Law of Poetry), in which no offering was
made to demons; for the profession of the poet, he said, was pure, and
should not be subject to the power of the devil. He left to the poets,
however, the gift of extemporaneous recital, because it was acquired
through great knowledge and diligent study, but all other rites he
strictly forbade to the poets of Erin.