Others claimed his origins were hidden because he was Jewish or secretly working as a double agent for the Portuguese royal family.

But the latest theory suggests that the great navigator, who died in 1506 after four voyages to the New World, was in fact of royal blood: the son of King Vladislav III who was supposedly slain in the Battle of Varna in 1444.

In his third book on the subject Manuel Rosa, who has spent 20 years researching the life of Columbus, suggests that Vladislav III survived the battle with the Ottomans, fled to live in exile on the island of Madeira where he was known as "Henry the German" and married a Portuguese noblewoman.

Mr Rosa believes a conspiracy was agreed to hide Columbus' true origins and to protect the identity of his father. "The courts of Europe knew who he was and kept his secret for their own reasons," the researcher at Duke University, North Carolina said.

"Our whole understanding of Christopher Columbus has for 500 years been based on misinformation. We couldn't solve the mystery because we were looking for the wrong man, following lies that were spread intentionally to hide his true identity," Mr Rosa told The Daily Telegraph.

His high birth would explain how Columbus was able to himself marry the daughter of a Portuguese noble 15 years before he set out to prove the world was round.

"The marriage was approved by the King of Portugal something that could never have happened if we believe the myth that Columbus washed up in a shipwreck in Portugal," Mr Rosa explains in his book "Colon: La Historia Nunca Contada" – Columbus: The Untold Story", published in Spain last month.

"His knowledge of geography, astronomy, algebra, cartography and even the fact that he used a secret cipher to communicate with his brothers all point to the best education. He was clearly a scholar and not self taught as the myth goes."

Mr Rosa claims to have proved that a last will dated 1498 in which Columbus wrote "being I born in Genoa" was forged 80 years after his death by Italians with the name Columbo who wanted to lay claim to his inheritance.

Other evidence supporting Mr Rosa's theory includes the similarity of Columbus's coat of arms with that of the Polish king and a painting of the explorer housed in the Alcazar in Seville in which a crown is hidden on his sleeve.

And the fact that he was "reddish-haired, fair skinned and blue eyed – all features commonly found in Poland."

The next step is to try and prove Columbus's royal heritage by extracting DNA from the tombs of Polish kings to compare with that of the explorer's son who is buried in Seville Cathedral.

"I have made a request to the Cathedral in Krakov to examine remains from the tomb of Vladislav II, who could turn out to be the grandfather of Columbus. It would prove the truth of my theory," said Mr Rosa.

A project launched five years ago to discover Columbus' true origins using DNA comparisons between his family and possible descendants was not conclusive.

A team of scientists took samples from his tomb in Seville and from bones belonging to his brother and son and compared them with the genetic make-up of 477 people living across Europe with surnames believed to be modern-day variants of Columbus.