The island in question was Britain, by then already a naval force to be reckoned with. Writing in 1733, Voltaire apparently imagined a future time when it would seem incongruous to the French that Britain could ever have been a great power. He did not say how far distant that time might be, but perhaps it has finally arrived, after 261 years.
In Paris last week, the French Institute for International Relations produced a survey of world affairs which included a lengthy 'British dossier' that painted the picture of a country bypassed by history.
To study Britain, said the Institute, was to study decline. Beset by desperate economic and social problems, the British could think only of cheap sex scandals and empty political infighting. They turned their backs on Europe but failed to recognise that the United States no longer valued their friendship. Education and learning were so badly neglected that the country had slipped far behind its rivals, and even the current economic recovery had served only to highlight British shortcomings and hypocrisy.
Voltaire's England could hardly have been more different in character; indeed he was so impressed that he was even prepared to praise the English above his own countrymen: 'The French are of so flexible a disposition . . . that the monarch needs but command and he is instantly obeyed. The English generally think, and learning is had in greater honour among them than in our country.'
He wrote from first-hand knowledge, having spent more than two years in London, in 1726-28, during which he met Alexander Pope, Jonathan Swift and John Gay, was presented to George I and Sir Robert Walpole, attended the theatre often and mastered the language well enough to swear 'bloodily' (according to a friend) and write several literary works in English.
He came to publish an epic poem on French history, entitled La Henriade, which he thought would land him in trouble if produced in France. England was then, to many in on the Continent, a land of liberty and a refuge from autocratic monarchs. When Voltaire published his Letters Concerning the English Nation some years later he found no reason to depart from that view.
'The English,' he wrote, 'are the only nation who have been able to prescribe limits to the power of kings by resisting them; and who by a series of struggles have at last established that wise government where the Prince is all-powerful to do good and at the same time is restrained from committing evil; where the nobles are great without insolence . . . and where the people share in the government without confusion.'
The tax arrangements are such that 'no one is tyrannised over, and everyone is easy. The feet of the peasants are not bruised by wooden shoes; they eat white bread, are well clothed and are not afraid of increasing their stock of cattle nor of tiling their houses, from any apprehension that their taxes will be raised the year following.'
Voltaire was particularly impressed by English prowess in trade, which he thought tended to increase liberty and engender tolerant attitudes. 'Take a view of the Royal Exchange in London,' he urged, '. . . where the representatives of all nations meet for the benefit of mankind. There the Jew, the Mahometan and the Christian transact together as though they all professed the same religion and give the name of Infidel to none but bankrupts.'
He found his English hosts - even the nobility - attached to learning and science. A discussion of the ideas of Isaac Newton, whose funeral he witnessed in 1727, fills much of the Letters. Newton and Descartes are compared, broadly to the advantage of the Englishman.
Voltaire could, however, be critical. Shakespeare, he said, may have been a genius, but he 'had not so much as a single spark of good taste, or knew one rule of the drama'.
And he could be wrong: 'The English,' he wrote, 'are not fired with the splendid folly of making conquests, but would only prevent their neighbours from conquering. They are not only jealous of their own liberty, but even of that of other nations.' Within 30 years India, Canada and countless other distant lands had been conquered, and the British Empire was born. But that, as the French Institute would undoubtedly point out today, is history.