LONDON - French author and philosopher Voltaire had surprisingly close ties to the aristocracy during his stay in England during the 1720s which helped shape his thinking, newly-discovered letters reveal.

Professor Nicholas Cronk, director of Oxford University's Voltaire Foundation and lecturer in the Medieval and Modern Languages Faculty, came across 14 previously unknown letters by the "Candide" writer during archival research.

Two of them in particular shed new light on the friendships he developed during his two-and-a-half year stay in England, when he was in his 30s.

"Voltaire came to England as a relatively unknown poet with only a recommendation from the British ambassador to Paris, so to make the aristocratic connections that he did shows him to be a brilliant social climber," Cronk said.

It is known that Voltaire was exposed to the ideas of English writers and later took empiricism back to France where it became the basis of the Enlightenment.

But the details of this relatively undocumented passage of his life offer fresh evidence as to how he may have came about that knowledge.

In one letter, Voltaire writes to Lord Bathurst, a patron of the arts who often hosted great English thinkers at his manor, Richings, including Alexander Pope.

Voltaire thanks Bathurst for "the freedom of your house and the many liberties I enjoyed in that fine library".

Cronk said the message showed how Voltaire would have been exposed to the likes of William Shakespeare, Isaac Newton, John Locke, Pope and others -- both by reading their books in the library at Richings and possibly by meeting contemporary English thinkers.

"It's clear from the letter that Voltaire was part of the Bathurst circle, spent time in his house and worked in his library," Cronk told Reuters.

"This gives us a sense of Voltaire being integrated into the literary life of England under George II."

In another letter, Voltaire writes to the Treasury to confirm receipt of a 200 pound grant from the king and signs his name "Francis Voltaire", the only known example of him using the English version of his first name.

"He is someone who reinvents himself a bit," Cronk explained.

"Lots of other French Enlightenment figures come to England, but as visitors. He comes for two and a half years, learns English and becomes a part of English society."

Voltaire admired England's openness and the relative fairness of its legal system -- he only left France to avoid a lengthy prison sentence for quarrelling with a young nobleman.

Cronk said he believed there were more undiscovered Voltaire letters to be unearthed.

"Voltaire wrote tens of thousands of letters and there are still more to come to light, but the ones about England are precious because they are rarer.

"Voltaire was famous later on. When he was younger, though, he was not such a megastar, so people didn't keep his letters so much."