ALLAN RAMSAY’s celebrated portrait of the Genevan philosopher Jean Jacques Rousseau is perhaps one of the most famous portraits of any exile. The Scottish philosopher David Hume had assisted Rousseau to flee from France in 1766. He commissioned his compatriot Ramsay (1712-78) for a portrait in which the sitter wears Armenian dress, a heavy cloak and a fur hat, that was much commented upon by bemused Londoners.

I was put in mind of this great treasure of the National Gallery of Scotland in Edinburgh by the recent exhibition at the RA of another Genevan contemporary: Jean-Etienne Liotard. His 1770 portrait of the Roman Catholic traveller William Constable FRS was painted in Lyons. It is weaker, as so many of Liotard’s works are, lacking the psychological brilliance shown in his Scottish counterpart’s work; but Constable, too, wears Armenian dress.

Was this simply an affectation of the time or does it say something about Armenia? That Rousseau chose to dress in this way suggests that Armenia was very much at the centre of enlightened European consciousness, despite the country’s geographical distance. This exhibition marks the centenary of the much disputed genocide there.

Archbishop William Laud (d. 1645) was Chancellor when, in 1635, he presented the first Armenian manuscripts to the library. The expansion of the library’s collections from the Near East is largely a phenomenon of the later 19th century, thanks to the diligence of Edward Nicholson, who was Bodley’s Librarian for 30 years until the eve of the First World War. He acquired the oldest book on display, a hymnal and a collection of antiphons from the psalms, which is dated to 1295.

This exhibition is the inaugural show in what was the “New Bod”, which has now been reconfigured to provide a café, shop, exhibition space, and — oh yes, I almost forgot, as it is given so little prominence on the building’s street glass façade — a library, housing all the special collections.

But Theo Martin van Lint and Robin Meyer have gone well beyond the treasures held by the library itself. The college across the road, Wadham, has loaned an Armenian translation of Cardinal Giovanni Bona’s 1671 Direction to Heaven. It was translated in Rome in 1674, and was intended as a proselytising tool to bring Armenians over from Orthodoxy. Rome was obviously less worried at the time by Anglicanism, with a king who was broadly sympathetic to papal claims, and the English version followed only in 1680. The Cistercian Bona had died in 1674.

Wadham has also loaned an 18th-century translation of the writing of the third-century Neo-Platonist Porphyry, published in Madras in 1793; Armenians had long lived in India in the safety of the Mughal empire of Akbar.

The University of Manchester has loaned a late copy of Alexander the Great’s Romances, copied in Sulu Manastir, in the city on the Bosphorus previously known as Constantinople, in 1544, by Bishop Zacharia Gnunec’i. The work had first been translated into Armenian in the fifth century, from a lost Greek original and had remained popular.

On closer inspection, the illuminated illustration of the famed horse Bucephalus appears as a terrifying fiery animal with claws, composed of animals and human figures; even the claws turn out to be little birds with open beaks.

It is not all about books. The V&A has loaned a pastoral staff, a vardapet; and from private collections come photographs, demitasse coffee cups exported from Staffordshire, lace and crochet work, and 20 coins, the earliest of which are tetradrachms that are dated to the reign of Tigranes the Great, 140-55 BC.

The exhibition concludes on a chilling note with a map detailing centres of the Armenian genocide, routes of death marches, and escape routes, from R. E. Hewsen’s Historical Atlas (University of Chicago, 2001).

If Downing Street is lining up the President of Turkey next for the red-carpet treatment in the wake of kowtowing to travelling despots from China and Egypt, this exhibition in Mr Cameron’s old university would make a good starting-point.

It is, as the title implies, about a celebration for a culture that has endured, often without much support from Christians elsewhere. President Putin would also learn from it.

“Armenia: Masterpieces from an Enduring Culture” is at the Weston Library, Bodleian Libraries, Broad Street, Oxford, until 28 February. Phone 01865 287400. www.bodleian.ox.ac.uk