Irish hagiography is not my cup of tea. But when Cahill & Company puts an author in its green pantheon, I move. Frederick Buechner's Brendan is definitely Cahill green. For those of you ignorant (like me) of the Irish saints, Brendan was born in 484 and lived for ninety-four years. Thus he is in the generation after St. Patrick, when the Ould Sod was still full of pagan sods.
When you get right down to it, Brendan himself hadn't made the voyage entire between the superstitious vindictive life of the Druids to the forgiving ethos of Christianity. That's is the book's magic, making clear (and moving) how arduous that transition really was. It's written in a marvelous literary dialect that I can only call Book of Kells English, Kenglish, a faux archaic peasanty way of speaking that is a perfect metaphor for the tricky voyage of discovery the new Christians are engaged in.
For example, Brendan believes he can sail in a primitive boat with a crew of five to find the Land of the Blessed. (There is growing evidence that Celtic monks did in fact make landfall at Newfoundland and later maybe Florida.) They do find a monk whose isolation has forced him over the hill, and when they ask him if St. Patrick is here in this Land of the Blessed, he has them taken to a red-haired monkey. When they see small children miming coupling in this false Eden, he knows his life as a "blue martyr" (one who has dedicated his life to isolation on the endless sea as opposed to the more traditional "white martyr" who is a hermit of the desert).
In a fit of pique he sends another monk to save one who is drowning. That monk's guilt at his loss of the friend triggers a spiritual voyage for both Brendan and Malo when the saint makes that monk his confessor. That relationship becomes a daily hell on earth for both of them until they "discover" the meaning of Christian forgiveness. It retrieves the cliches of Christian living to a newer and deeper truth as they learn to implement the insights of the Faith in the brutal and unforgiving land of Irish paganism.
The narrator for most of the book is Brendan's childhood friend, Finn, so that we see the saint at a close distance as he wrestles with his own demons--his own sense of worthlessness in the face of those who need more than he can give them, his own doubts about the validity of his Faith, capital F. For ever gain there is a loss that never fades. Brendan is taken as a prodigy from his parents in infancy to be devoted to the new Faith. He is a natural leader and hundreds and hundreds sign up for the monastic centers he founds.
Then he gets off on a cockamammy scheme to find the Land of the Blessed, and subjects his closest friends to the most intimidating perils. It is a weird world in which a candidate for king who has only one testicle is disqualified and the Amazonian Maeve agrees to risk her virginity to check him out.
It is a world of magic power in which Brendan saves his friends from hostile enemies on the road by doing and knowing things only the supernaturally gifted could do. His charisma converts the Bard MacLennin to the counselor (and later saint) Colman.