The Most Ancient Lives of Saint Patrick/The Life and Acts of St. Patrick/Chapter 172
He banisheth the Demons forth of the Island.
And the demons grieved for their lost dominion, and assailing the saint they tormented him in his prayers and his fastings; and they fluttered around him like birds of the blackest hue, fearful in their form, their hugeness, and their multitude, and striving with horrible chatterings to prevent his prayer, long time they disturbed the man of God. But Patrick being armed with His grace, and aided by His protection, made the sign of the cross, and drove far from him those deadly birds; and by the continual sounding of his cymbal, utterly banished them forth of the island. And being so driven away, they fled beyond the sea, and being divided in troops among the islands which are alien unto the faith and love of God, there do they abide and practise their delusions. But from that time forward, even unto this time, all venomous creatures, all fantasies of demons, have through the merits and the prayers of the most holy father Patrick entirely ceased in Hibernia. And the cymbal of the saint, which from his frequent percussions thereof appeared in one part broken, was afterward repaired by an angel's hand; and the mark is beheld on it at this day. Likewise on the summit of this mountain many are wont to watch and to fast, conceiving that they will never after enter the gates of hell; the which benefit they account to be obtained to them of God through the merits and the prayers of Patrick. And some who have thereon passed the night relate them to have suffered grievous torments, whereby they think themselves purified of all their sins; and for such cause many call this place the Purgatory of Saint Patrick.