After the Lutheran revolution, which set out to bring the Church back to its basic values, the backlash of the baroque period began. The aim of the art of the Counter-Reformation was to project itself, to stun, to exhort the people, to rein them in with the most spectacular bombast, to snare them back into the bosom of the Roman Church.

In the baroque era the treatment of unfurling unrealistic drapery, blown by unseen winds into fluttering convolutions, reached dizzying heights. Not only were holy events translated into a turbulence of fleshly shapes, but satin, silk and damask fluttered away in lavish extravaganzas. An originally humble faith, so strangely re-invented, still bewilders us modern viewers.

The so-called Baroque (derived from the word barroco which means misshapen pearl) in the 16th and 17th centuries went in many directions and flowed in many tendencies. This exhibition does little to explain this, but rather shows artists activities at European courts. Here is only a grab-bag of lendings, somehow perplexing, weighted down with gobelin tapestries, arms and medals, and random portraits of saints and patrons by minor masters. However the work by the two greatest artists of the period, Velsquez in Spain and Bernini in Rome, is so outstanding that it makes a visit to the show a must.

Bernini! I dont think any other artist ever so dominated a city. Sculptor, architect, city planner, painter, Gianlorenzo Bernini (1598-1680) held all Rome in his hand. The first shape of Rome was that of the Roman empire. The second shape was the baroque Rome of Bernini. Both are still in our daily life. An art dictator, Bernini planned all to the last detail. Our main squares Piazza Navona, Piazza Barberini, St Peters Square like giant salons or stage sets of magnitude are finely calibrated to absorb masses of ambulating people, multiple sight and sound. Spectacles in them, complete with mime events, music, lavish banquets and fireworks, were the order of the day. And then most importantly, in the spacious churches meant to draw large crowds to listen to the preaching Jesuits, and in the villas of the aristocrats, Bernini installed those dynamic, almost turning, marble carvings of his.

In this show there are first of all some beguiling models for his astounding fountain of the rivers in Piazza Navona. Among them is a small terracotta of the ever-thirsty old lion a mangy beast, modelled in all its laxness, touchingly observed. Two busts of Christ, with long intricate curls and shoulders wreathed in typically baroque drapery, are tour-de-force master carvings. But despite his ambitious temporal drive, Bernini had a deep faith. This is surprisingly revealed here in two oils on canvas. There is his Christus Patiens, a nude, tired young man, just beginning middle age, his flesh getting soft, despairing in all his body language. The other, smaller, Christo Deposto is even more shattering in its frankness. This is a poor male body, just worked over by the police or thugs. Both nudes are God, but also suffering human flesh abused by the ignorant. For the Baroque, these oils are works of astounding simplicity.

Neither is Diego Velsquez (1599-1660) too lavish in all his marvellous portraits here. They are of a mute grandeur.

Over the years the Spanish court painter portrayed his patron and friend King Philip IV of Spain over and over again, as if he were an eternal riddle to solve, or as an exercise. In the portrait here, Philip is already middle-aged, with his flaxen curls lanky and his chin heavy. As ever he is clinically but also kindly observed. The two larger oils of the two court jesters, poor little maimed individuals so proud and stern in their finery, and one with a silky big dog, are bravura acts of sympathetic portraiture studies of strange creatures, live toys for the royals, in elegant clothes. The little infanta Margherita, in all her cumbersome frock barely manages a smile. And Marianna of Austria the big queen with her big face painted in all its pink plainness, ensconced in an impossibly elaborate hairdo and even more complicated clothes, as complex as a landscape is painted not only with patience, but a sly lively wit. In all of these, and the slightly melancholy self-portrait, unobtrusive skill is coupled with profound scrutiny of character. And all is brushed as still, velvety surfaces, into images of mysterious impact. Velsquezs power is veiled and adored by other painters, who can never have enough of that mirrored room full of royal children and their toy dwarfs Las Meninas in the Prado.

Luca Giordano who painted at the court of Naples, was extremely facile and typical of the Baroque and therefore amply represented here. But where are Rubens, Borromini, Caravaggio, Artemisia Gentileschi, the Carracci and many other artists of the period? A row of self-portraits of the protagonists is intriguing, and so is a small painting by David Teniers, showing a collector of the period surrounded by his collections. The mounting of the works on charred wood panels is unfortunate, and the music coming from the slide show on the stairs is irritating.

The riddle of the Baroque is not solved here. For us the fundamental puzzle is its paradox between ostentation (heavy illusionism, restless posing, lurid exaggeration) and faith. But Bernini and Velsquez because they are true artists, go beyond. In the canvases by Bernini and the cool magically applied layers of paint by Velsquez, nothing is blunt or obvious. Nothing is loud. There is a quiet search for the inner being. And this reflects the inner being of the masters as well.

Velsquez, Bernini, Luca Giordano. Le Corti del Barocco. 12 Feb-2 May. Sun-Thurs 10.00-20.00. Fri-Sat 10.00-22.30. Scuderie del Quirinale,

Via XXIV Maggio 16, tel. 0639967500, www.scuderiequirinale.it.

Picture: Velsquez's portrait of Marianna of Austria shows the queen in all her pink plainness.