Cayo Largo, named after its geographical shape, appears for the first time in the Reports of the Captain General of the Island in the 17th century. Nevertheless, investigations carried out in the key prove that its first discoverers were actually aboriginals of the 14th and 15th century.
During recent archaeological researches, it has been demonstrated that the first inhabitants of the key were the so-called "Guayabo Blanco" Amerindians, descendants of the Siboney culture. The Guayabo were good sailors and lived on fishing and hunting. It has been proven that they knew the fire and lived outdoors. They are claimed to be the authors of the rustic paintings found at Punta del Este, Isle of Youth, considered to be almost a thousand years old.
It has also been demonstrated that the Admiral Christopher Columbus visited the key on his second visit to Cuba, on his way from the island San Juan La Evangelista (today's Isle of Youth) to the bay of Jagua (today´s Cienfuegos Bay).
However, what constitutes the highest historical attraction of the key is the pass through its territory, proven by nautical records, of famous pirates and privateers that once populated the seas. Some examples are the periodical visits of John Hawkins from 1565, usually accompanied by the "Terror of the Seas": Francis Drake; the long stay on the key, used as headquarters, of the French Jean Laffite and Latrobe in 1819; and the pass of the widely known Henry Morgan when he was on his way to attacking the city of Puerto Príncipe and buried all his treasures in the key in 1666.