Islands of Ireland: Trasnagh na dtonnta to this County Down island

Luscious green grass for the herd of cattle brought here for the first time in more than 70 years

Trasnagh Island, Strangford Lough, County Down. Picture: Dan MacCarthy

The Annals of the Four Masters has a much more colourful explanation for the geographic origins of Strangford Lough in the North than the prosaic geological textbooks inform us. The latter are correct, of course: the lough’s supposed 366 island (an exaggeration that merits comparison with Clew Bay’s similar claim) were formed by retreating glaciers at the end of the last ice age about 12,000 years ago. And like Clew Bay in County Mayo, they left behind hundreds of islands peeping above the surface comprised of their stony deposits, and sometimes storied deposits.

The medieval manuscript on the other hand relates how at Loch Cuan (original Irish name) in 1654BC “an inundation of the sea over the land at Brena which was the seventh lake eruption that occurred in the time of Parthalon and this is named Loch Cuan”. This did not occur any more than the Earth being formed in 4,004 BC did as surmised by the 17th century Bishop of Armagh James Ussher according to his interpretation of the Book of Genesis.