Cormac Ua Liatháin was a 6th-century Irish saint who is only known from Adomnan of Iona's Vita Columbae.
On the first occasion, Columba prophesied that Cormac had just set sail from the district of Erris beyond the river Moy that day to find a place of retreat but found none.
Columba prophetically knew all about this, and, being in Pictland with King Bridei I at the time and knowing that Cormac would find his way to the Orkney islands, which at the time were a sub-kingdom under the Picts, requested that the King should make sure that if any of his brethren came to the Orkney islands, they would be treated well.
His ship was driven by a steady southerly wind for fourteen days which pushed him very far to the north.
Columba, who was present in spirit, was aware of what was happening and he called his monks to come and pray together for Cormac.