Hy-Brasil

Hy-Brasil — also written Hy-Breasal, O Brasil, or Brazir — is one of the most persistently documented phantom islands in European cartography. It first appears on the Portolano chart of Angelino Dulcert in 1325, placed as a perfect circle off the west coast of Ireland, and continued to be charted by mapmakers across Europe until the 19th century, long after most mythological islands had been dropped from navigation charts.

In Irish mythology, the island is bound in mist and surfaces from the Atlantic only once every seven years, briefly visible but impossible to reach before it sinks again. It is described variously as the dwelling place of the Tuatha Dé Danann — the divine race of pre-Christian Ireland — as a land of perpetual youth and abundance, or as the realm of an immortal philosopher-king. The name is thought to derive from Breasal, a mythical High King of the World in early Irish tradition. Several historical expeditions set out specifically to find it: an expedition from Bristol in 1480 is recorded as searching for it, and in 1674, a Scottish sea captain named John Nisbet claimed to have landed there, describing ancient black rabbits and a silent old man who briefly broke the enchantment.

The persistence of the legend has attracted various explanations. Some scholars connect it to the Porcupine Bank, a shallow submarine shelf west of Ireland occasionally exposed by extreme low tides, which could have produced real sightings of land that subsequently vanished. Others note that the Irish tradition of the Tír na nÓg and the Otherworld islands of early mythology — Tír fo Thuinn, Mag Mell, Emain Ablach — provided a deep cultural template into which recurring glimpses of Atlantic mirage were fitted. The name was later transferred to the country of Brazil by Portuguese navigators, though the etymology remains disputed.