For more than five centuries, mapmakers drew a mysterious circular island off the west coast of Ireland called Hy-Brasil. Sailors reported glimpsing it through fog, cartographers copied it from chart to chart, and Irish legend said it appeared only once every seven years.
No one ever found it, yet it survived on official maps into the 19th century. Here's the real story behind one of history's most persistent phantom islands.
Hy-Brasil (also spelled Hy-Breasal or Brasil) is a legendary phantom island long said to lie in the Atlantic Ocean west of Ireland.
The name likely comes from the Irish "Ui Breasail," meaning "descendants of Breasal," a legendary Irish clan or king name — not a reference to modern Brazil.
In Irish folklore, the island was said to be shrouded in mist and visible to human eyes only once every seven years.
The earliest known map showing the island is a 1325 nautical chart by Genoese cartographer Angelino Dulcert (also known as Angelino Dalorto), who labeled it "Bracile."
The island appeared as a perfect red circle on the 1375 Catalan Atlas, a color scheme cartographers sometimes used to mark it as an unusual or unverified place.
Hy-Brasil also appeared on other historic maps and charts over the centuries, including versions attributed to the Ottoman admiral Piri Reis and the Flemish cartographer Abraham Ortelius.
Bristol merchants were searching for a mythical "Isle of Brasil" in the Atlantic in the 1480s and 1490s, around the same period John Cabot sailed west from England in 1497 in search of new lands.
According to a widely repeated legend, a Captain John Nisbet claimed in 1674 that his ship encountered dense fog off the Irish coast, and that Hy-Brasil emerged from the mist once the fog lifted.
The island was drawn as a circular landmass, sometimes shown with a river or strait running through its middle, on many of the maps that included it.
Some historians think Hy-Brasil began as a simple cartographic error or a misplaced, exaggerated sketch of a real landmass, such as Rockall or a shoal in the North Atlantic.
Other theories suggest sightings of the island were optical illusions, such as Fata Morgana mirages, which can make distant clouds or the horizon look like solid land.
Hy-Brasil was quietly dropped from British Admiralty charts in 1865, after cartographers concluded it was a geographical error that had simply been copied from map to map for centuries.
Even after it was removed from official charts, at least one reported sighting of Hy-Brasil was recorded in 1872, years after mapmakers had already abandoned it.
The Irish poet Thomas Moore referenced the legend in his 1810s song "O'Brazil, the Isle of the Blest," which romanticized the mythical island.
The legend of Hy-Brasil has been linked in popular culture to the broader myth of Atlantis, as both describe an advanced or blessed land lost to the sea.
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