St. Brendan's Isle is one of the oldest phantom islands of the Atlantic, named after one of its first explorers. Known as Brendan the Navigator, this Irish abbot born around the year 489, is believed to have traveled extensively, as far as the Hebrides, Orkneys, and the Faroe Islands; some think he made it farther, to Iceland and possibly even North America. He died in 577, and about 200 years after his death a book titled Navigatio Sancti Brendani Abbatis (The Voyage of Saint Brendan the Abbot) appeared, describing his travels. This book was widely copied and translated until the 1400's.
In the book, Brendan is told about the "Promised Land of the Saints" by another saint who has been there, Saint Barrind. Saint Brendan and more than a dozen monks set sail to find this island. They travel for seven years, encountering many things such as a griffin and a devil-whale. Finally they find the island, which is an earthly paradise, but they have to return home. They return with fruit and precious stones from the island. The story of Brendan (later Saint Brendan) was much exaggerated to provide allegorical lessons. Despite this, some of the things and places described seem to correspond with actual locations. For instance, they sail through a "coagulated sea". This could be a description of the icy seas found between Greenland and Canada. They pass a "silver pillar wrapped in a net" in the sea, possibly a description of an iceberg. They pass an island of blacksmiths, who throw slag at them, possibly Norse settlers of the Orkneys. They find a volcano, and the third latecomer is taken by demons down to Hell. Iceland has active volcanos. For these reasons, some argue that, like the Vinland Sagas (once thought to be a fiction), The Voyage of Brendan was based on fact.
Origins of the story:
Here is a case where seafaring legends cross-fertilized. As a genre, The Voyage of St Brendan is an example of a form of literature popular in the seventh and eighth centuries in Ireland called an immram. These were tales of a hero's series of adventures in a boat, often in search of an Otherworld, or an enchanted island far to the west, sometimes hidden behind a veil of mist.
In the more pagan of these stories, the name for this island is Tír na nÓg (Land of the Young), a paradise reached by entering ancient burial mounds or caves, or by going across the sea or under the sea. It is inhabited by a supernatural race in Irish mythology, the Tuatha Dé Danann, who fled Ireland in ancient times. The island is often invisible to regular mortals unless invited.
In The Voyage of Brendan, this voyage-to-the-otherworld theme meshed with a religious ascetic tradition where Irish monks would travel alone in boats, (the same way their desert brothers used to isolate themselves in caves), and the Otherworld is inhabited by angels or saints. Tír na nÓg becomes Tír Tairngire (the Land of Promise), a terrestrial paradise promised by God.
Many episodes that appear in The Voyage of Brendan appeared before, in two older imramma, The Voyage of Mael Duin and The Voyage of Bran. The island of sheep, the island of birds, a thieving crew member who later dies, the island of blacksmiths, the island with a hermit who wears only hair for clothing, the silver pillar/column sticking out of the ocean are episodes that appear in one or both of these source tales.
It is likely that Irish immrama also were also influenced by Homer’s Odyssey — a sea-voyage in which a hero with a few companions wanders from island to island, meets other-worldly wonders, and finally returns home. (Ancient Greek literature was read and preserved in Ireland at this time.)
As a geographical location:
On maps, Saint Brendan's Island first appeared on the Ebstorf map of 1235, in a location where the Canary Islands are. Other early maps confused the location with the Madeira Islands or the Azores. As this region became explored and mapped, Saint Brendan's Island seemed to move northward, to regions that were not as well known. It appeared on maps up into the early 1800's.
Honorius of Atun called it the Lost Isle in his 1130 book on geography, saying "There is in the Ocean a certain isle agreeable and fertile above all others, unknown to men but discovered by chance and then sought for without anyone being able to find it again and so called the "Lost Isle." It was, so they say, the island whither once upon a time St. Brandan came."
In Mapamundi de Hereford (1275), it is described as an archipelago called “The Isles of the Blessed and the Island of St Brendan”.
In the 18th century the idea came about that only the worthy could see the island through the mist. In 1719, the Scottish monk Sigbert de Gembloux reported seeing the island, as did Don Matea Dacesta, mayor of Valverde, El Hierro in 1721. According to the Canary historian Ramirez, in 1723 a priest performed the rite of exorcism towards the island during one of its apparitions behind low cloud.
In 1759 a Franciscan monk wrote: "I was most desirous to see the island of San Borondon and, finding myself in Alexero, La Palma, on 3 May at six of the morning, I saw, and can swear to it on oath, that while having in plain view at the same time the island of El Hierro, I saw another island of the same colour and appearance, and I made out through a telescope, much wooded terrain in its central area. Then I sent for the priest Antonio Jose Manrique, who had seen it twice previously, and upon arrival he saw only a portion of it, for when he was watching, a cloud obscured the mountain. It was subsequently visible for another 90 minutes. Being seen by about forty spectators, but in the afternoon when we returned to the same point we could see nothing on account of the heavy rain."
In his Noticias, Vol I, 1772, chronicler Viera y Clavijo wrote: "A few years ago while returning from the Americas, the captain of a ship of the Canary Fleet believed he saw La Palma appear and, having set his course for Tenerife based on his sighting, was astonished to find the real La Palma materialize in the distance next morning." Viera adds that a similar entry is made in the diaries of Colonel don Roberto de Rivas, who made the observation that his ship "having been close to the island of La Palma in the afternoon, and not arriving there until late the next day", the officer was forced to conclude that "the wind and current must have been extraordinarily unfavourable during the night."
Further expeditions were organized in the search for the island, but from the 19th century onwards, reported sightings of Brendan's Isle became less frequent.
While the story is often assumed to be a religious allegory, there has been considerable discussion as to whether the legends are based on actual events. Some take it as evidence that the Irish were the first Europeans to reach North America. Tim Severin has demonstrated that it is possible that a leather-clad boat such as the one described in the Navigatio could have reached North America. Severin's 1978 film The Brendan Voyage documented this feat.