By the 15th century it was considered insurmountable by Arabs and Europeans, thus resulting in the name meaning cape "no" in Portuguese.

[2] The thirteenth-century Genovese navigators Vandino and Ugolino Vivaldi may have sailed as far as Cape Non before being lost at sea.

It was named Cabo do Não ("Cape No") by Portuguese mariners during the fifteenth century, being considered the impassable limit for Arab and European sailors, the non plus ultra beyond which no navigation could occur.

[3] "Quem o passa tornará ou não" (whoever passes it will make it or not), wrote Venetian explorer Alvise Cadamosto in his book Navigazione.

Starting in 1417, exploratory vessels were sent by Prince Henry the Navigator, managing to cross Cape Non and reaching Cape Bojador, then considered the southern limit of the world, stretching into the "dark sea"[4] (Latin Mare Tenebrarum, Mare Tenebrosum or Bahr al-Zulumat in Arabic), the medieval name for the southern Atlantic Ocean, inaccessible to the sailors of the time.