Renaissance Siena : Art For A City, National Gallery, London

By Michael Glover

Curators are forever rooting around for new ideas for shows. Some ideas are fairly obvious because certain artists are such giant presences, and there is always a good deal more to be said about them and their ever outwardly rippling influences.

The next major monographic exhibition about Picasso to hitLondon is provisionally scheduled to open at Tate Britain in 2011, for example, and it will deal in part with his reception in Britain.

What about the Renaissance, though? Well, recently there have been big, monographic shows about Leonardo, Raphael, Titian and Tintoretto, to name but four. A little trickier is the themed show. This new one at the National Gallery deals with one particular Italian city-state over a period of about 100 years, from the middle of the 15th century to the middle of the 16th.

That city-state is Siena, which looks today almost as bristly and battlemented as it did back then. This is a promising idea, and it has not been done before.

Why do it, though? Well, shows are often about filling gaps in our knowledge. We feel we know an awful lot aboutRome, Venice and Florence during the Renaissance, about the development of those cities, and the artists who worked in them.

How much do we know about Siena? By comparison with those others, relatively little as a major, productive cultural centre – other than the fact that its presence today is a powerful, physical reminder of its past greatness, and that it has great art in its cathedral and its museums. It is not definedby the presence of certain great artists as, for example, Florence is defined by the presences of Michelangelo and Fra Angelico, and Padua by Giotto.

This exhibition argues that Siena was just as important in its own way as these better known culturalcentres and, as solid proof, itbrings together more than a hundred examples of works produced in and for Siena during that period.

The show begins powerfully enough – with a series ofpaintings that show Siena as a defiantly proud presence in a dangerous world of shifting political allegiances. The second work in the show, TheCoronation of Pope Pius II, dated 1460 andattributed to Francesco di Giorgio, whose works we will find ourselves staring at repeatedly, brings together three potent visual symbols.

We have an image of the Virgin Mary hovering like some pious humming bird over a newly elected Pope, who just happens to be Sienese, hurrah. The city is present, protected by its soaring, ruddy, battlemented walls. There are armorial devices, too, registering the presence of the great families who will strive to make Siena even greater than its rival, Florence. So there you have it: the power of politics rudely enmeshed withthe undeniable authority of God’s mother. The scene embodies the twin spirits of defiance and watchfulness. The painting is undeniably potent. It is also fairly crude.

Now what Siena needed, notonly to make itself great, but also to be perceived to begreat and influential, was thepresence of great artists within its walls. It lured Donatello there – and there is one Donatello in this show. And so we proceed a series of rooms that tell the story of Siena’s beautification – how its churches, public buildings and the wall of its palaces came to be hung with newly painted treasures, and of the themes that were chosen – often mythological and classical, of course, because Siena so desperately wantedto emulate the greatness of the past.

We go through the exhibition slowly because we want the theme to succeed. We want to be shown masterpiece after masterpiece. We want it proven that Siena was as brilliant, in its heyday, as Venice and Florence in theirs. It never quite happens. For the most part, the paintings in the exhibition compare very poorly with some of the great Renaissance paintings you can see upstairs.

Even the painter who gets the largest room to himself, Beccafumi, popularly called the Sienese Giotto, is not a patch on Giotto, although a couple of his drawings in red chalk are two of the best pieces in the show. Quite a good idea though, and one that hadn’t been done before. It may not be done again for a while.

To 13 January (020-7747 2885)