Next Wednesday evening, the Palio hits the piazza. Report by Michael Sheridan. Photographs by Francesco Cito
The traveller in an antique Italian world of galleries and loggias often wonders why the horses always seem so mighty and predominant in the paintings and sculpture of the Renaissance.

With their great muscular flanks, flaring nostrils and flailing hooves, the beasts often outrank their riders. It is as if they claimed the artist's attention with such compelling force that their human cargoes appeared of little import.

In Siena, the horse still rules supreme, and in the greatest horse race in Italy, the Sienese Palio, the jockey counts for little. On 16 August, when the second Palio of the summer is run (the first is in July), visitors will see why. For all that matters in the Palio is that the winning horse crosses the line. If the rider is thrown and lies groaning in the dust, that is of little concern.

This bareback contest consumes the attention of Siena's citizens for months in advance and its ceremonial occupies days of preliminary parading, feasting and collective worship. But the race itself is all over in about 90 seconds - just as long as it takes for the ten contestants to gallop three times around the Campo, a vast scallop-shaped piazza at the centre of Sienese life since the 13th century. Its cobblestones are covered with sand and padded barriers are erected to preserve life and limb of racers and spectators alike.

These modest precautions apart, the Palio is a contest of such naked ferocity and emotion that every year yields its crop of broken bones and bruised egos. Its roots go deep into Siena's plague-ridden and factional history, dividing the city's 17 wards - the contrade - into a seething mass of rivalries and intrigue. The jockeys are brought in from the Maremma, the swampy lowlands of southern Tuscany, where they are presumed to be immune from the hallucinatory addiction that membership of a contrada confers on its initiates. But rumour has it that they are not all immune to the lure of a few million lire. Furtive talk of doping circulates in the alleys and cafes of Siena before the race, while furious discussion of its filthy tactics (almost everything is permitted) provide gossip long into the sharp Tuscan autumn. If there was ever such as thing as a stewards' inquiry at the Palio it would probably be conducted only into the quality of the food at the post- race banquet.

Everything about the race is adorned with mediaeval ritual. Although there are 17 contrade, only ten may race. So the first arguments arise over the lots drawn for the places, the mounts, the jockeys and the starting places. Since the Palio is staged in honour of the Virgin Mary, a copious number of rosaries are recited and numerous blessing invoked in each contrada to confer victory on the meritorious.

Then on 13 August, the ten horses that have emerged from the selection are paraded before a trial race. Over the next two days, four more trials will be held, with esxcitement mounting and banquets in the streets on the night of the Feast of the Assumption, 15 August.

The next morning a heavy-headed groom leads each horse to the chapel in its contrada, where it is blessed by the priest amid a subdued throng. Frequently the animal makes a great show of being dragged into church. Horseshoes and Renaissance marble steps do not seem to go happily together. If the horse, by now somewhat disconcerted, should dump a steaming pile of droppings in the aisle, that is viewed as a propitious exercise of the equine bowels.

At about five o'clock parades converge on the Campo in a riot of heraldry. The scene would help the least observant visitor to connect the present day to the brilliant colours typical of Sienese painting in the Palio's early centuries. Drummers, flag-wavers and musicians process and display their skills, as if a contingent of Orangemen had dropped acid and woken up smiling in the papist cauldron of Chiantishire.

After all this, the race itself is almost an anticlimax. The crowds press forward, the rope drops, the horses cram the pen then burst on to the track, screams and hoots of derision resound in the Campo, hooves beat on the sandy cobbles, pockets are picked, lovers are squeezed, lungs filled with gasping intensity, eyes strain for the leader - and suddenly it ends. The winner gallops onwards and out of the Campo, pursued by a delirious throng from his contrada who will carouse until the small hours. The Palio itself, a silken banner of immense antiquity, is presented to the victorious contrada and carried off to be venerated for the rest of the year.

Anybody can go to the Palio, but anyone who has not parted with up to pounds 200 for a seat will share the delights of the Campo with several thousand enthusiastic and volatile members of the citizenry.

Personally, I liked the Campo as I once found it on my birthday, 12 December, when no more than a dozen individuals cluttered its amphitheatric slopes and a bright winter sun illuminated lunch and a flask of wine spread on an outdoor table. For those who are prefer their horses in the art of Duccio and the Lorenzettis, this is a better way to see Siena. But that is all a matter of taste