The Fortunate Isles or Isles of the Blessed (Greek: ? , makár?n nêsoi) were semi-legendary islands in the Atlantic Ocean, variously treated as a simple geographical location and as a winterless earthly paradise inhabited by the heroes of Greek mythology. The related idea of Brasil and other islands in Celtic mythology are sometimes conflated with the Greek sense of islands in the western Mediterranean: Sicily, the Aeolian Islands, the Aegadian Islands or other smaller islands of Sicily. Later on the islands were said to lie in the Western Ocean near the encircling River Oceanus; Madeira, the Canary Islands, the Azores, Cape Verde, Bermuda, and the Lesser Antilles have sometimes been cited as possible matches.
According to Greek mythology, the islands were reserved for those who had chosen to be reincarnated three times, and managed to be judged as especially pure enough to gain entrance to the Elysian Fields all three times. A feature of the fortunate islands is the connection with the god Cronus; the cult of Cronus had spread and connected to Sicily, in particular in the area near Agrigento where it was revered and in some areas associated with the cult of the Phoenician god Baal.
Flavius Philostratus' Life of Apollonius of Tyana (v.2) says, "And they also say that the Islands of the Blessed are to be fixed by the limits of Libya where they rise towards the uninhabited promontory." In this geography Libya was considered to extend westwards through Mauretania "as far as the mouth of the river Salex, some nine hundred stadia, and beyond that point a further distance which no one can compute, because when you have passed this river Libya is a desert which no longer supports a population".
Plutarch, who refers to the "fortunate isles" several times in his writings, locates them firmly in the Atlantic in his vita of Sertorius. Sertorius, when struggling against a chaotic civil war in the closing years of the Roman Republic, had tidings from mariners of certain islands a few days' sail from Hispania:
...where the air was never extreme, which for rain had a little silver dew, which of itself and without labour, bore all pleasant fruits to their happy dwellers, till it seemed to him that these could be no other than the Fortunate Islands, the Elysian Fields.
It was from these men that Sertorius learned facts so beguiling that he made it his life's ambition to find the islands and retire there.
The islands are said to be two in number separated by a very narrow strait and lie 10,000 furlongs ( 2,000 kilometers / 1,250 miles ) from Africa. They are called the Isles of the Blessed. [...]
Moreover an air that is salubrious, owing to the climate and the moderate changes in the seasons, prevails on the islands. The North and East winds which blow out from our part of the world plunge into fathomless space and, owing to the distance, dissipate themselves and lose their power before they reach the islands, while the South and West winds that envelop the islands sometimes bring in their train soft and intermittent showers, but for the most part cool them with moist breezes and gently nourish the soil. Therefore a firm belief has made its way, even to the barbarians, that here are the Elysian Fields and the abode of the Blessed of which Homer sang.
Pliny the Elder's Natural History adds to the obligate description--that they "abound in fruit and birds of every kind"--the unexpected detail "These islands, however, are greatly annoyed by the putrefying bodies of monsters, which are constantly thrown up by the sea".
The Isles are mentioned in Book II of A True History by the Greek satirist Lucian of Samosata. The author makes fun of the heroes residing there by giving an account of their petty squabbles as presented to the court of the magistrate, Rhadamanthus. He goes on to describe other observations of how the residents occupy their time, using every opportunity to satirise both contemporary life and Greek mythology.
Lucio Russo, in L'America dimenticata, puts forward the bold hypothesis (supported by means of statistical methods) that the Fortunate Isles were actually the Lesser Antilles and that Hipparchus knew their longitude with remarkable precision.