Lost Worlds · Traditional location: Atlantic, west of Ireland

Hy-Brasil, the Phantom Isle

An island that spent 548 years on official maps without existing — and whose afterlife now includes a starring role in UFO lore.

Mainstream: Charted from 1325 (Angelino Dulcert) until 1873 (British Admiralty); origin a cartographic and folkloric compositeAlternative: Claimed as a real island — identified by some with Porcupine Bank, allegedly exposed in the last Ice Age53.40°, -13.60°

Lost Worlds Myth

At a glance

Hy-Brasil, the Phantom Isle — Photo: Abraham Ortelius (1572) · Public domain

Hy-Brasil is the Atlantic's most persistent phantom: a roughly circular island, often drawn split by a central channel, that first appeared west of Ireland on Angelino Dulcert's portolan chart of 1325 and was not finally deleted from British Admiralty charts until 1873, by then demoted to 'Brasil Rock'. Bristol merchants sent ships to find it in the 1480s, John Cabot's backers associated his landfalls with it, and Irish tradition wove it into tales of an enchanted isle — visible once every seven years through the mist — that fishermen off the Aran Islands called Little Aran. It has no connection to the country of Brazil, which is named after brazilwood. The island's pin on this globe marks Porcupine Bank, the shallow plateau 200 kilometres off Ireland most often nominated as its 'real' location.

See it on the globe →

The mainstream view

What archaeology says

Historians of cartography read Hy-Brasil as a self-perpetuating map error dressed in borrowed mythology. Barbara Freitag's study Hy Brasil: The Metamorphosis of an Island (2013), the fullest modern treatment, argues the island began as a cartographic feature — its name probably deriving from the medieval trade word for red dye-wood or an Italian toponym, only later folk-etymologised into Irish as Ui Breasail, 'descendants of Breasal' — and that the 'ancient Celtic Elysium' framing is largely a 19th-century literary retrofit. Once Dulcert drew it, successive chartmakers copied it for five centuries, because early cartography had no mechanism for proving a remote island absent: a captain who failed to find it had simply missed it in fog. Donald S. Johnson's Phantom Islands of the Atlantic (1994) documents dozens of such copy-along islands, with Hy-Brasil merely the longest-lived.

The 'sightings' dissolve on inspection. Roderick O'Flaherty's 1684 account relays a story of a man supposedly abducted to the island and returned with healing powers; the famous 1674 landing report of Captain John Nisbet — complete with giant black rabbits and a castle-dwelling magician — was a literary hoax; and the antiquarian T. J. Westropp, who reported watching an island appear and vanish off the Clare coast in 1872, was almost certainly describing a superior mirage (Fata Morgana), an optical effect well documented off Ireland's west coast. Low cloud banks, mirages and the real but submerged Porcupine Bank — discovered by sounding in 1862, its shallowest point still some 145–200 metres under water, far too deep to have been an island even at the lowest Ice Age sea levels — jointly explain the phantom without any land at all.

Key evidence cited

Freitag's analysis: the name and island are cartographic in origin, with the Celtic mythology attached retrospectively
Five centuries of charts copy one another, with the island shrinking and drifting as surveys improved
The 1674 Nisbet landing account is a demonstrated literary hoax; other sightings match Fata Morgana mirages
Porcupine Bank's shallowest depths (roughly 145–200 metres) rule out emergence even at glacial lowstand
Systematic Admiralty surveying in the 19th century found only open ocean, ending with deletion in 1873

The alternative view

What the skeptics propose

The romantic case holds that so durable a tradition should have a kernel. Irish folklore about a blessed western isle predates any surviving map, belonging to the same imaginative family as Tir na nOg and Saint Brendan's Isle, and believers argue Dulcert charted a living oral tradition rather than inventing one. Porcupine Bank remains the favourite candidate: proponents note that it is a genuine bathymetric high in roughly the right place, and speculate that parts of it, or of shallower banks since eroded, broke the surface within human memory of Ireland's first settlers — a claim mainstream marine geologists reject on depth grounds, but which keeps the geomythological possibility alive in popular accounts. Sceptics of the sceptics also point out that multiple independent witnesses, Westropp among them, believed absolutely in what they saw; the debate is over interpretation, not sincerity.

Hy-Brasil's strangest modern chapter is ufological. In 2010 Jim Penniston, one of the US airmen involved in the 1980 Rendlesham Forest incident, revealed pages of binary digits he said he had telepathically received from a landed craft; when decoded, they yielded garbled coordinates that enthusiasts matched to the traditional position of Hy-Brasil, spawning claims that the phantom isle is a dimensional portal or ancient advanced base. Analysts who have examined the notebook — including software engineers who worked through the binary character by character — note that it decodes only via modern ASCII conventions, contains formatting and error patterns consistent with recent composition, and surfaced three decades after the incident; even many UFO researchers treat the 'Hy-Brasil coordinates' as a later embellishment rather than data. The episode is a textbook case of one legend colonising another.

Key evidence cited

Irish otherworld-island traditions (Ui Breasail, Tir na nOg) plausibly predate the first charts
Porcupine Bank is a real shallow plateau close to the island's traditional charted position
Multiple sincere eyewitness reports across centuries, including Westropp's 1872 account with independent witnesses
Bristol's repeated 1480s search voyages show contemporaries treated the island as findable, not fabulous
The Rendlesham binary 'coordinates' are cited by UFO researchers as pointing to the traditional Hy-Brasil position

Genuinely open questions

Did Dulcert's 1325 chart record an existing Irish oral tradition, or did the folklore grow up around the map?
What combination of mirage, cloud and low island effects best explains the most detailed sighting reports?
When did the Ui Breasail etymology first become attached to the island, and by whom?

Worth knowing

The 1674 'landing' on Hy-Brasil reported an island inhabited by enormous black rabbits and a lone magician living in a stone castle — details that helped later scholars recognise the whole account as satire.