TURKS Royal Academy of Arts, London, until April 12.
"It mutilates you if you cannot read the language of your grandparents' tombs," says a Turkish friend. This applies not only to tombstones, but to great swaths of poetry.
When Turkey was set up as a republic in 1923, the desire was to escape the Ottoman past, which was regarded as corrupt and backward, with its harems, pyramids of skulls and an official language and alphabet that few of its people could make out.
Back then, it was modernising Turkey that interested the world. And she has done very well in an area notorious for trouble.
Indeed, the success of the Royal Academy's Turks exhibition shows organisation and scholarship of a very high level. It tries to cover the entire past of the Turks, from their origins on the border of China right up to 1600, when they ran a world empire whose rulers referred to themselves as "marcher lords of the horizon".
In its nature, the theme is too big. But an exhibition, to adapt Constant, can only designer ce qu'elle voudrait definir .
Turks is excellent, with artefacts on display from several great museums.
It covers subjects that have long interested the best archaeologists - beginning with Sir Arminius Vambery in the middle of the 19th century.
Vambery was a Hungarian refugee in Constantinople at a time when the Hungarians were pondering their origins, given that their language has much back-to-frontness and Lego-ness in common with Turkish. He found his way to Central Asia and talked to an interested local ruler but discovered that the linguistic similarities were superficial.
Perhaps music might reveal a connection, suggested the emir, whose court orchestra proceeded to play on broken vacuum cleaners for several hours.
Vambery then sang Don Giovanni to represent his native music.
The emir was sufficiently impressed to give him every help in excavating cave paintings buried under the Taklamakan Desert in northwest China, some of which are displayed here. They reveal the Turk's roots in a strange mixture of civilisations - Buddhist, Hellenistic, Chinese, Turkic and even Christian influences.
The curious thing about Turkic empires is that they wore religion very lightly. For Turkish secular nationalists, these Chinese antecedents were important: they supplied a past that was non-Islamic. But the fact is that the 16th century - as displayed here - is the breathtaking part of the exhibition. And inevitably that means Islam at its classical greatest - extraordinary illustrated books, clothing and Koran-stands.
The organisers could hardly have explained, although the catalogue attempts to, that Islam of that period was far removed from the aesthetically unappetising and repetitive version that followed. The Ottoman 16th century is a resplendent phenomenon.
One good question: what did it owe to Byzantium? On the evidence here, not much, though the music and the running of the state followed Byzantine examples, and many Byzantine aristocrats went over to the service of the Ottoman state.
This exhibition is a splendid introduction to a world nowadays difficult to understand but endlessly rewarding when you make the effort. I remember a BBC programme in which a woman droned on and on about the ills of "The Turk". The cameraman, clearly bored, just got on with wonderful images of Istanbul. Good for him.
Norman Stone is professor of international relations at Bilkent University, Turkey.