The most famous incident in the Voyage is when the crew land on what they think is an island... but they are in for a big surprise! Of course, the saint knows better:
When they came to another island, the boat drew to a halt before they were able to reach the harbor. Saint Brendan instructed the brothers to get out of the boat and they did so. They tied down the boat on both sides with ropes until it could make port. The island, however, was rocky, without any grass. There were sparse woodlands and there was no sand on the shore. While the brothers were spending the night in prayers and vigils on shore, the man of God stayed inside the boat, for Saint Brendan knew what sort of island this was but he did not want to tell the brothers, lest they become terrified. When morning came, Saint Brendan ordered the priests to each say the Mass, and they did so. When Saint Brendan had said Mass himself on the boat, the brothers began to carry raw meat off the boat in order to salt it, along with fish which they had brought from the previous island. When they had done this, they put a cauldron on the fire. When they had added wood to the fire and it had started to boil, the island began to move like a wave. Then indeed the brothers began to run to the boat, begging for the protection of the saintly father, and one by one he grabbed them by the hand and pulled them into the boat. Having left behind all the things which they had carried over to the island, they set sail. Next, the island was drawn down into the ocean. Then they could see the fire burning at two miles' distance. Saint Brendan told the brothers what it was: "Brothers, are you wondering what happened to the island?" They said, "Yes, we do wonder greatly, and we were stricken with a great fear." Saint Brendan said to them, "My little sons, do not be afraid, for God has revealed to me in the night by means of a vision the mystery of this thing. Where we were is not an island, but a fish. It is greater than all the creatures swimming in the ocean, and seeks always to join its tail to its head, but it cannot do that because of its length. Its name is Iasconius."Here is the Latin text:
Cum autem venissent ad aliam insulam, cepit illa navis stare antequam portum illius potuissent tenere. Sanctus Brendanus precepit fratribus exire de navi et ita fecerunt. Tenebantque navim ex utraque parte cum funibus usque dum ad portum venit. Erat autem illa insula petrosa sine ulla herba. Silva rara erat ibi et in litore illius nihil de arena fuit. Porro pernoctantibus in orationibus et in vigiliis fratribus foras de navi vir Dei sedebat intus. Sanctus vero Brendanus sciebat qualis erat illa insula sed tamen noluit illis indicare ne fuissent perterriti. Mane autem facto precepit sacerdotibus ut singuli missas cantasset et ita fecerunt. Cum ergo sanctus Brendanus et ipse cantasset missam in navim ceperunt fratres crudas carnes portare foras de navi ut condidissent sale et etiam pisces quos secum tulerunt de alia insula. Cum haec fecissent posuerunt cacabum super ignem. Cum autem ministrassent lignis ignem et fervere cepisset cacabus cepit illa insula se movere sicut unda. Fratres vero ceperunt currere ad navim deprecantes patrocinium sancti patris.At ille singulos per manus trahebat intus. Relictisque omnibus quae portabant in illam insulam ceperunt navigare. Porro illa insula ferebatur in oceanum. Tunc poterant videre ignem ardentem super duo miliaria. Sanctus Brendanus narravit fratribus quod hoc esset dicens: Fratres admiramini quod fecit haec insula?" Aiunt: "Admiramur valde nec non et ingens pavor penetravit nos." Qui dixit illis: "Filioli mei nolite expavescere. Deus enim revelavit mihi hac nocte per visionem sacramentum huius rei. Insula non est ubi fuimus sed piscis. Prior omnium natancium in oceano querit semper suam caudam ut simul iungat capiti et non potest pro longitudine quam habet nomine Iasconius".If you enjoyed that, Saint Brendan has many other fabulous adventures that you would definitely like!
The story of the island that is really a fish or a whale is a famous story throughout world folklore. For example, there is a great version of the story in the Voyages of Sindbad. In the Christian tradition, the Physiologus contains the story of the tracherous island, complete with an allegorical interpretation.
I have a special fondness for the voyage of Saint Brendan, because when I was a graduate student in Comparative Literature at Berkeley, one of the other Latin students decided that we should get on a boat, journey "across the waters" to Angel Island in San Francisco Bay, and read the Navigatio out loud in Latin to each other while we were on the island. It was so much fun! Admittedly, Angel Island is not quite "The Island of the Blessed," but we had a really great time.
Here is a lovely illustration of Saint Brendan and his sailors from a medieval manuscript: