ARCHITECTURE: Holy smoke

It was the rescue of the Holy Shroud that grabbed headlines when Turin Cathedral caught fire. But the real story, says Jonathan Glancey, is about Guarino Guarini, architect of the fantastic baroque chapel which held it

Visitors to Turin will doubtless find themselves ambling along the arcades of Corso Mario Trematose in the near future. Corso Mario ... who? Trematose, the gallant fireman, and instant national hero, who saved the Holy Shroud from destruction by fire last week. To do so, Trematose bludgeoned his way through sheets of bullet-proof glass and braved the falling stucco, marble and masonry of the blazing chapel as this most holy of Catholic holy places became Hell incarnate.

The cynical, or heathen, might pour cold water on Trematose's heroics. After all, if the Shroud is nothing more than a medieval fake, surely the Bishop of Turin could commission a replacement? There are plenty of young artists, even those teaching at the Prince of Wales's Institute of Architecture in London, who would be happy to take possession of a fresh cadaver, crucify it and impress the tortured flesh on to yards of antique linen.

In any case, and long before the Reformation, there were at least five Holy Shrouds doing the rounds - those of Besancon, Cadouin, Champiegne, Xabregas and Lirey - the last of which came to rest in Turin in 1578. As long ago as 1389, the Bishop of Troyes appealed to Pope Clement VII to resist the cult of the Shroud, as the one from Lirey, he said, was known to have been painted by a local artist some years before.

No matter, for the Shroud, whatever you believe, became an object of widespread devotion and a significant tourist attraction for Turin. Just as well. Look along the shelves of even the most liberally stocked bookshop and you are unlikely to find a guide dedicated to Piedmont, the region of which Turin is capital, and much less to the city itself. Turin is written off in those guides that are available as an industrial city of precious little interest.

Nothing could be further from the truth. Turin is a great and fascinating city and not least because of the fantastic buildings of Guarino Guarini (1624-83), priest, philosopher, mathematician, playwright, and architect of Santissima Sindone, the chapel of the Holy Shroud.

Guarini is to Turin as Gaudi is to Barcelona, yet this most brilliant of Baroque designers is largely unknown outside scholarly or Torinese circles. This is possibly either because Turin is overlooked or because Guarini was, for centuries, written out of history or belittled.

When news of the seven-hour blaze that shot Mario Trematose to fame was seared into newspaper reports, only one report (filed by my colleague Andrew Gumbel in Rome) appeared to be aware of the importance of Guarini's invaluable masterpiece.

The Shroud might be an inspired fake, but the chapel that has housed it since its completion 330 years ago is one of the most brilliantly original of all buildings. It has only recently undergone a major two-year restoration. The damage done to it is incalculable. Its loss would be unthinkable.

Anyone who has ever climbed up the steep flights of curving stairs that lead from Turin Cathedral to the Santissima Sindone will have the impact of Guarini's design impressed on their mind's eye for life. It is a magnificent, exquisite and seemingly impossible space that soars up into the infinite through tier after tier of filigree stone arches superimposed on one another in a geometry that at first defies description, let alone understanding. Here, architecture is suspended in space. Space and light. Its message is clear even to the sceptic: this is Christ's resurrection represented in stone and the human spirit soars with that of the risen saviour.

Here is one of those architectural experiences one dreams of, but rarely encounters: space that connects the finite with the infinite and a building that expresses its purpose in every stone. It is a masterpiece, but not by consensus.

In fact, there was a virulent reaction to Padre Guarini and all his works in the years following his death. In his Memorie dei piu celebri architetti (Rome, 1768) F Milizia wrote: "Whoever likes Guarini's architecture, much good may it do him, but he would be a nitwit." Stefano Ticozzi's Dizionario degli architetti scultorri, pittori & etc (Milan, 1830), was even more lascerating: "He [Guarini] died, to the advantage of art, in 1683."

As late as 1913, Martin Briggs, honorary secretary of the Royal Institute of British Architects, felt justified in claiming: "For sheer lunacy of design they [Guarini's buildings] would be hard to parallel." (Baroque Architecture; London, 1913).

The British fear of Roman Catholicism and the all-pervasive influence of John Ruskin, a critic for whom Baroque architecture was sin frozen in stone, meant that the restoration of Guarini's reputation even in scholarly circles was a long time in coming.

Fortunately, since 1988 we have been able to turn to H A Meek's masterly Guarino Guarini and His Architecture (Yale University Press), which has put the picture straight. Guarini, Meek argued, understood perfectly well how, in the words of 17th-century Jesuits, "to catch men's affections and to ravish their understanding" through sensual architecture as much as by Scripture and preaching.

His genius, however, was to push "architectural creativity and inventiveness beyond the familiar Baroque world of emotional manipulation and trompe- l'oeil illusionism".

Guarini was not a Jesuit, but a member of the Theatine Order of "clerics regular" established in 1524. This was 10 years before the founding of the Jesuits by Ignatius Loyola. Like the Jesuits, Theatines were highly educated Papal shock-troops at the front line of the Counter- Reformation. The order produced several important architects who understood how to design religious buildings that could very nearly raise the divine soul from the corrupt body.

Guarini was born, one of five brothers, in Modena in 1624. All five joined the Theatines. Guarini trained in Rome, where Borromini was very much at work, and was ordained priest in 1648. He was elected Provost of the Modena Theatines in 1655 (the top job), but was bullied out of the appointment by Prince Alfonso, viceroy to the Duke of Modena, who had his own favourite.

For the next 11 years, Guarini travelled and worked, as priest, university teacher and architect, in Messina, Lisbon and Paris. The churches or parts of churches he designed in these cities have all since been destroyed by earthquake or fire. A devout Protestant might see a divine hand at work here, particularly so when we learn that the Theatines were suppressed in France in 1795 and that St Anne-la-Royale, the Parisian church Guarini remodelled, was used as a dance hall and cafe before demolition in 1823.

The architect returned to Turin in 1666, and two years later was appointed Ducal Engineer (to the House of Savoy-Piedmont) for the chapel of the Holy Shroud. He had already been at work on the equally magnificent, if less highly charged, church of San Lorenzo, which in itself makes a trip to Turin worthwhile.

He also designed the astonishing and exquisite Palazzo Carignano, another unlikely Torinese gem. Between the royal palace and the cathedral, Guarini raised his unparalleled nest of Baroque domes above the elevated marble floor from which rose the daunting silver altar of the Holy Shroud.

Guarini died on a trip to the printers in Milan to proof-read the pages of his last book, Coelistis Mathemathica. His triumphal buildings may have been rubbished over the next three centuries, but today his legacy is clear.

Not only did he prove that it is possible for inspired individuals to create an architecture almost entirely of their own making (Gaudi, Mackintosh or Le Corbusier, for example, did so too), but Guarini demonstrated that buildings can have an almost tangible soul.

Certainly Turin would be the poorer without his astonishing legacy. The centre of the city was laid out, famously, on a rigid and memorable grid by Asconio Vitozzi: Guarini's sensual forms break Vitozzi's grid and make the centre of the city resemble the board of "Snakes and Ladders".

Mario Trematose may be the hero of the moment, and the Holy Shroud an object of renewed veneration (and curiosity), but the name that deserves to be resurrected in Turin after last week's tragic fire is that of Padre Guarino Guarinin