The Navigatio Sancti Brendani Abbatis, more usually known as the Navigatio or Voyage of Brendan, had been written in Latin and described how Saint Brendan, living in the west of Ireland, had been visited by another Irish priest who described to him a beautiful land far in the West over the ocean where the word of God ruled supreme. Brendan built a boat specially for the voyage and set sail with seventeen monks to find this Promised Land. They had a long and hard journey, wandering from one island to another, and had many adventures, until they finally won through to their destination and managed to explore the fringe of the Promised Land before setting sail once again for Ireland.

In J.R.R. Tolkien's poem Imram (Sea voyaging of Brendan) Saint Brendan at the end of his life recalls the three things that he remembers from his voyage: "...A Cloud, a Tree, a Star."