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. This was due to the cape running far out into the sea, causing it to break and appear dangerous. "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" (
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. ==References==