What is Hy Brasil?

Legend tells that somewhere off the coast of Ireland there was an island, always covered by intense fog and only seen on very rare occasions. Every seven years the fog would fade away, revealing this fabulous land. Mountains, green fields and a glowing city were briefly visible. This Celtic land was the home of fairies, magicians and wizards. Legends and myths of ancient Ireland contain many references to heroes who, attracted by this fantastic vision, launched into the sea in search of it. Anyone able to touch the island would achieve eternal life in a delightful paradise. But every time they approached it, the island disappeared again below the sea.
Peter Beresford Ellis, author of several books and dictionaries about the Celtic world, confirms that the Irish mythology and old chronicles contain many stories of Hy Brasil, dating from a thousand years before the Portuguese discovery of Brazil. Beresford Ellis explains that the term Hy Brasil derived from Old/Middle Irish, around the tenth century. Hy is a variation of í, which means island, and that is why we also find the form I-Brasil, or the Island of Brasil. The word Brasil, argues Beresford Ellis and many other authors, comes from the root bres, meaning ‘mighty, great, beautiful’, which gives origin to the name Breasal, a god in Irish mythology. We also find Bresal as the high king of the Celtic world, and the island of Bresal was known as the place where he used to establish his court every seven years. Hy Brasil is also compared to many other mythical islands, such as Tir na nÓg, the land of eternal youth.