St. Senan it was said, was directed to Inis cathaigh/Scattery Island by Raphael the Archangel. Up to this point the Island was reputedly inhabited by a monster or Cathach as he was called. The Cathach ate any man or beast daring to venture to Inis Cathaigh.
The Archangel brought Senan to a viewing point on the mainland from where he showed him the Holy Island. He told Senan that God had sent an awful monster to keep the sacred Island while awaiting Senan’s arrival. The Archangel said that God wanted Senan to build a church on the Island, which would become a head of devotion and a well of wisdom to the rest of the world. Senan agreed that he would bow to the will of God. With that, Senan was raised up on a flagstone where he had been sitting and was then set down upon a high hill in the middle of Inis Cathaigh. This spot on the Island has since been known as Ard na nAingeal (The Angel’s Height).
They then sang praise to God at this spot and from there went to seek out the Cathach. On seeing the unwanted visitors to his Island the Cathach arose, fiercely, angered that anyone should dare to come visit him on his Island. So hideous,uncouth,ruthless,awful was the beast that arose there, with a horse’s mane and flaming eye, the earth trembled beneath his feet as he made for Senan. Then Senan made the sign of the Cross in the Cathach’s face, the monster was silent, and Senan banished it in God’s name from Inis Cathaigh to Doulough Lake near Mount Callan to dwell without harming anyone again.
The degree to which fact and fiction are mixed in this story will never be known, but the fact remains that St. Senan was a holy man who is still remembered throughout Ireland and beyond for his many works.