Aztec artefacts: The art of sacrifice

The British Museum's exhibition of Aztec artefacts is full of truly stunning pieces, says Tom Lubbock – but behind the beauty lies a viciously bloody cult

There is no document of civilisation that is not at the same time a document of barbarism," said Walter Benjamin, German critic, meaning that the Europe we pride ourselves on, for its fine arts etc, is also the Europe of war, exploitation etc. To which somebody retorted, vice versa: "There is no document of barbarism that is not at the same time a document of civilisation."

A smart answer. But if everybody has a bit of both, then all you can do is try to do the accounts, and see – in any given case – how civilisation weighs against barbarism. Take those crazy Aztecs. Magnificent treasures and accomplishments. Systematic human sacrifice on an unheard of scale. Does one set off the other?

Moctezuma: Aztec Ruler is the last of a series of exhibitions at the British Museum devoted to spectacular men of power. The First Emperor: China's Terracotta Army, Hadrian: Empire and Conflict, Shah Abbas: the Remaking of Iran were the three preceding, and none of them were exactly pussycats. But Moctezuma – well, he was famous for his sternness, but there was probably nothing personally psychopathic about his body count. It was the system.

Many of us were brought up to call him Montezuma. This is an Anglo corruption. (He appears under this name in John Dryden's play The Indian Emperor.) But now he's Moctezuma. Aztec, too, should be dropped, and after the exhibition's title – a concession to the needs of publicity, presumably – the proper name of this mesoamerican people, Mexica, is always used.

I'm all for authenticity, but these culture-history experiences never really work for me. They have divided intentions. They want to display some fantastic pieces of artwork, in a way that has you looking at them as individual, isolated objects. And they also want to knit these objects into a larger account, which it would take a full book to tell.

That book is available. There is the excellent catalogue to the exhibition, which will tell you all about the Aztecs' way of life, Moctezuma's reign (1502-20), Cortes's invasion, Moctezuma's mysterious death, and the manner in which death and afterlife were treated in Aztec culture – a fascinatingly awful story. But when the show itself becomes a show of evidence, all sorts of problems arise. Beautiful Aztec works alternate with crummy Spanish paintings that only have a documentary value. And there just aren't enough Aztec works to do an adequate evidence job. They've been lost on a massive scale, or they're too precious, or too big – the remains of the Templo Mayor being an obvious example – to be shifted.

Art, evidence... and then there's a third aspect to these exhibitions. Atmosphere. Through various effects the visitor is to be transported across time and place. The blowing of a conch shell is sounding somewhere off. There are panoramic projections showing the landscape around Aztec territory, with its volcanic skyline. And the show's centrepiece has four very large light boxes, each showing a vertical view of a flight of stone steps, which we're to understand are staircases down which sacrificial blood would have cascaded. (Look up and overhead, weirdly, you see the dome of the old Reading Room.)

No actual blood is shown. The show is trying to evoke mood while being very careful to avoid any dodgy reconstruction. The spectre of Mel Gibson's ludicrous Apocalypto – notionally about the Maya, but no matter – hangs horribly over the whole project and must be kept out of our minds if at all possible. The nearest we're allowed to the sight of blood is a tiny scale model of the Sacred Precinct of the capital Tenochtitlan, where the model makers have run a fine brush dipped in red paint down the stairways of the various pyramid temples.

In this story, destruction goes every way. One reason that so many of the Aztec treasures got lost or destroyed is that they were viewed by the Spanish conquerors as pagan idols and not, as we now do, as superb pieces of art. But this show too is strangely uninterested in their aesthetic qualities – well, it doesn't talk about them in its captions, it restricts itself to historical/archaeological information, even though it must be aware that the artistry of Aztec carving and inlaying is one of the main things that will be drawing visitors.

It seems to me that, having got together such remarkable pieces, they should tell us more about their visual and emotional language. There's the very distinctive stone low relief, where the figures – in their slightly squared shapes – are flattened as if they were pastry gone over lightly with a rolling pin. There's the mastery of half-abstracted natural forms, for example the basalt cactuses. Or again, the most beautiful thing here, I think, there's a greenstone heart, almost a sphere, with suggestions of armature and fruit. The heart is a subject unknown to Western sculpture, but the Aztecs of course had an interest. The focus of their sacrifices was the plucked out hearts of their prisoners of war, to be fed to the divine sun.

The heart is not alone. There are various other items that connect directly to the Aztec blood cult, like daggers and dishes, and their aesthetic satisfactions don't relieve us from questions of art and evil. It may have been a long time ago, but Aztec artworks present us with the same dilemmas as more recent ones. There's DW Griffiths' The Birth of a Nation – a pioneering work of cinema and racist propaganda that glorifies the Ku Klux Klan. There's Leni Riefenstahl's Triumph of the Will, ditto the Nazis. All these works are shown and watched with a degree of qualms, though people generally don't find them intolerable. You're meant to be able to separate their artistry from their viciousness.

Or take Renato Bertelli's elegant sculpture Continuous Profile of Mussolini. It's not a satire, it's a celebration of the dictator's firm features. Yet it's exhibited with enthusiasm, currently on view in Mark Wallinger's touring show, The Russian Linesman. But suppose it was Continuous Profile of Hitler. (A big counterfactual. Hitler's moustache disrupts his profile in a way that would make that imaginary work impossible.) Mussolini is just about OK, not quite evil enough. Hitler is surely beyond the limit.

And the Aztecs? Really too long ago? Or it was their culture? Or they knew no better? I don't know what the answer is, but I bring up these hard cases because I think we should feel something comparably queasy. Come to that, perhaps we should also feel queasy about Spanish religious painting when we remember the bonfires of the Inquisition. Perhaps we should remember that when the National Gallery has its Spanish religious art show later this Autumn.

But this "Moctezuma" show also holds more positive examples. Among its more evidential exhibits are a number of Spanish books giving the invaders' story and what they found. At least the writing is in Spanish, but the illustrations are in...? It's very often hard to tell whether the drawing belongs to the European or the Aztec tradition or both – one hand picking up the dialect of the other. Admittedly this graphic miscegenation was under force, and eventually nobody drew in Aztec (until 20th century Mexican artists started to imitate it). But the mix doesn't always go unequivocally one way. One of the most striking exhibits is a sculpture of a coiled plumed serpent, the god Quetzalcoatl – transformed into a baptismal font! Who can say who won?

Moctezuma: Aztec Ruler, 24 September-24 January, British Museum, London WC1 (0207-323 8181, www.britishmuseum.org)