quality:corruption, linguistic:paraphrasing, structural:summarization
Ancient

Plutarch in his Parallel Lives (Sertorius, 75 AD) referring to the military commander Quintus Sertorius (d. 72 BC), relates that after his return to Cádiz, he met sailors who spoke of idyllic Atlantic islands: "The islands are said to be two in number separated by a very narrow strait and lie 10,000 furlongs from Africa. They are called the Isles of the Blessed."

Archaeological evidence suggests that the islands may have been visited by the Vikings sometime between 900 and 1030.

Accounts by Muhammad al-Idrisi state that the Mugharrarin ("the adventurers" – seafarers from Lisbon) came across an island where they found "a huge quantity of sheep, the meat of which was bitter and inedible" before going to the more inhabited Canary Islands. This island, possibly Madeira or Hierro, must have been inhabited or previously visited by people for livestock to be present.