The maybe island

'Twas a wild and stormy night. The captain gathered his men around him and said, 'Lads, I'm going to tell you a story: 'Twas a wild and stormy night. The captain gathered his men around him…'

On such a night, when seafarers of old would tell stories to calm their fears, an Irish monk called Brendan was facing disaster in the middle of the Atlantic, bobbing in a tiny sailing ship made from ox hides. Accompanying him were seventeen fellow monks, all with hope in their hearts of discovering new heathen lands to convert to the Faith. Or probably by now with hopes of finding any kind of land on which to stretch their legs and catch a few dodos to make a change from stale cheese.

But on this fateful night the monks had fallen silent as the storm grew stronger and giant waves hurled their frail craft into dark canyons that threatened to swallow them. Up in the bows, the lookout held his hand in front of his face to ward off the stinging spray. Suddenly his companions heard him shout above the roar of the wind: 'Land ahoy!'

Rushing forwards they saw a vast, black shape approaching through the gloom. An island! (Cries of 'we're saved', 'thanks be to Providence' and so on.) They managed to steer alongside the island without crashing into it, leaped ashore to a rough, featureless surface and made their ship fast to any protuberances they could find.

By morning the storm was easing and the monks decided to remain on this strangely austere little island for a day or two to recover their strength and make a few repairs to their boat. However, their leader Brendan, a more experienced sailor than the others, soon broke the news that their island was moving. Cruising purposefully through the water, no doubt about it.

The explanation soon became clear. They had landed on a very large whale.

The monks decided to handle this disconcerting development as another manifestation of a benign Providence that was now offering to carry them across the ocean with zero effort.

Their whale proved remarkably tolerant, transporting them for forty days before delivering them safely to a real, solid island.

And what an island! This time, they found themselves in a land that could have been the long-sought Paradise on Earth, a splendiferous place clothed in lush vegetation where birds trilled, cool water gushed from springs and fish of a thousand colours frolicked in the clear waters around its beaches. They stayed on the island for seven years - and who can blame them? - before tearing themselves away to return to rainy Ireland.

In the centuries that followed, as the intrepid voyagers' story was told and retold, the little paradise they had discovered became known as Saint Brendan's island or, in Spanish, the isla de San Borondón. Those who try to extract grains of truth from ancient legends suggest it may have been the island of La Palma in what are now the Canaries. Or Madeira, or the Azores, or even America, nearly a thousand years before Columbus.

Or perhaps, more tantalisingly, it was the elusive eighth island that for many centuries was believed to exist somewhere west of the seven known Canary Islands. An island that sometimes is there, and sometimes is not…

Walk up to the highest point of La Gomera, the peak of Garajonay, and in the right conditions, in the right frame of mind, perhaps you will glimpse a strange formation of clouds on the western horizon, a vague, fluffy pillow of white mist such as might form above a little island. A gentle island clothed in trees, where spring waters flow, birds sing and imagination takes flight into all kinds of fancies.

Notes for the serious student

There are many versions of the legend of Saint Brendan or San Borondón, who set sail from Ireland in the sixth century AD in a small and flimsy vessel with a variable number of companions. He enjoyed a succession of weird adventures, of which landing on a whale is just one. In some versions they managed to celebrate Mass on the whale's back but it abandoned them soon afterwards. I prefer the version in which the whale is more helpful.

There are also many interpretations of the legend. The association of Brendan with the mythical extra Canary Island is one of those muddles that happens with legends, but it's a seductively attractive notion - an island that comes and goes, perhaps rising only to save sailors lost in the mists or wild weather. Sadly, modern satellite and marine survey techniques make it very easy to disprove this kind of thing, and what a shame that is.

However, the name San Borondón lives on in the Canaries as a usefully emotive tag for hotels, restaurants, apartment blocks and a brand of bottled water. Brendan himself, often known as Saint Brendan the Navigator, is the patron saint of whales and dolphins as well as sailors and travellers in general.

There is, of course, a real eighth Canary Island called La Graciosa, which never disappears but is very small and is normally counted with its larger neighbour, Lanzarote.

The engraving of Brendan's whale was digitised by New York Public Library from an early seventeenth century book by Caspar Plautius, abbot of Seitenstetten in Austria. It's not too accurate in respect of whales, nor of Brendan's boat, but it's the best we can do after all this time.