Claimed to have been first visited in 512 by the monk St. Brendan and 14 others, along with later reports up to 1772.
Said to lie in the Atlantic Ocean west of Ireland. Irish myths described it as cloaked in mist except for one day every seven years, when it became visible but still could not be reached.
Discovered in the early 16th century by Spain, but mysteriously vanished sometime during the 17th century. While no dominant theory holds, it is possible that the island submerged due to tectonic movements, supported by the existence of a seamount at 22°38.76′N 90°51.3′W / 22.64600°N 90.8550°W and the nearby Scorpion Reef.
Gaspar Frutuoso noted its discovery by João Vaz Corte-Real in 1472 in Saudades da Terra.
Discovered by Spanish merchant ship Aurora, currently thought to be just Shag Rocks.
Ancient Greek legend described by Plato, later hypothesized to be real, and depicted on a 1664 map by Athanasius Kircher.
Antillia (or Antilia) is a phantom island that was reputed, during the 15th-century age of exploration, to lie in the Atlantic Ocean, far to the west of Portugal and Spain. The island also went by the name of Isle of Seven Cities (Ilha das Sete Cidades in Portuguese, Isla de las Siete Ciudades in Spanish).
It originates from an old Iberian legend, set during the Muslim conquest of Hispania c. 714. Seeking to flee from the Muslim conquerors, seven Christian Visigothic bishops embarked with their flocks on ships and set sail westwards into the Atlantic Ocean, eventually landing on an island (Antilha) where they founded seven settlements.
The island makes its first explicit appearance as a large rectangular island in the 1424 portolan chart of Zuane Pizzigano. Thereafter, it routinely appeared in most nautical charts of the 15th century. After 1492, when the north Atlantic Ocean began to be routinely sailed and became more accurately mapped, depictions of Antillia gradually disappeared. It nonetheless lent its name to the Spanish Antilles.
The routine appearance of such a large “Antillia” in 15th-century nautical charts has led to speculation that it might represent the American landmass, and has fueled many theories of pre-Columbian trans-oceanic contact.