Sources and influences

A story which includes a sailor seems to have left its mark in The Lord of the Rings. The story is found in the Old English (Anglo-Saxon) poem The Battle of Maldon. It is about a confrontation between the commander of the Anglo-Saxon forces and the messenger of the Viking invaders. The messenger is called  'seafarer' or 'sailor' by and sent packing in no uncertain terms, but the bargain he offers and the threat that accompanies it echo in Gloin's story of the visits of Sauron's emmisary to the dwarves of the Lonely Mountain.

The legend surrounding St Brendan the Voyager (or Navigator) tells of his attempt to find the mythical 'Fortunate Isle', or the 'Isle of the Blest' which was famous in medieval times and believed to be real. The medieval monk Honorius of Augsburg declared that the island had vanished. Tolkien created several stories that echo St. Brendan's search for these wonderful but mythical places. One version of the Blessed Isle is Tolkien's Tol Eressea that is in sight of the land where the Valar dwell. It was the dwelling place of Elves and protected from the sight of mortals. Another version is Numenor, the great Island realm of Men until their kings became rebellious and set out to demand immortality from the Valar, for which their Island was drowned, vanishing Atlantis-like beneath the waves.
See Life and Voyage of St. Brendan