We talk about artistic celebrity as if it were a new phenomenon. But few artists have ever come close to the status and stardom once known by Gianlorenzo Bernini - sculptor, architect, painter and the designer of Rome as we know it. For popes and kings, he was more like a minister than an ordinary artist, someone to dine with and chat to as an equal. He was so important that when Louis XIV, the Sun King, wanted him to come to France for a few months to work for him - the only time in his adult career that Bernini was away from Rome for long - it was a subject of immense diplomatic negotiation.
Bernini was not just the friend of rulers but a popular star too. When he left Rome for France, crowds turned out to wave him off. All along the route to Paris he was feted and mobbed. He said he felt like a travelling elephant, an exotic beast everyone wanted to see. No wonder he felt cocky enough to mock Louis XIV to his face - although he made the definitive bust of the king that can still be seen at Versailles.
With today's appetite for the Baroque, he is a star of the Victoria and Albert's forthcoming exhibition of Italian terracotta sculpture, Earth and Fire - even with such rival attractions as Donatello and Giambologna. Bernini always did stand out.
Our idea of the artist is of a romantic outlaw sentenced by a hostile society to endless night: Michelangelo asserting his own vision against the Pope's demands; Caravaggio, murderer and outcast. But Bernini was born to sweet delight. He never seems to have had an unsuccessful day. Born in Naples in 1598, to a father whose career as a sculptor brought him to Rome to work for the Pope, Bernini was a prodigy. At the age of about 10 he was presented to Pope Paul V, who looked at his drawings, pronounced him the new Michelangelo, and invited him to take as much as his little arms could carry from a bag of gold.
That was pretty much the pattern of the rest of his life: working for successive popes, being compared to Michelangelo and getting paid a fortune. He died at 82, rich and honoured.
By rights, he should be forgotten now. Bernini himself predicted that he would be disparaged after his death, and he was - until the 20th century. He was seen as a messy, mixed-up artist in the 18th and 19th centuries. But in the 20th, the turbulent, excessive qualities of his art were rediscovered as the essence of the High Baroque. Today Bernini ranks with Rubens; they are the Baroque's supreme masters.
Bernini may have been a propagandist for the Counter-Reformation, he may have been a devoted servant of authority and power, but there's something personal about his art, even at its most public. Bernini shaped the very fabric of Rome, he devised imposing religious and civic spaces and icons of saints and monarchs; yet in the still centre of his swirling aesthetic is something intimate, subjective, that speaks on a very direct and unpretentious level.
Take his bust of the elegant British courtier Thomas Baker, half-man, half-spaniel, now in the V&A's British Galleries. Baker was sent to Rome with Antony van Dyck's triple portrait of Charles I, depicting him from three points of view so as to provide Bernini - who had never met the king - with a template for a bust in which he would dramatise, as he did so well, the virtues of absolute monarchy and its corollary, Catholic faith.
While there, Baker commissioned Bernini to do his own bust. The result was a playful, friendly portrait of the foppish cavalier. The royal bust was destroyed in the Whitehall Palace fire in 1698, so this is all that survives of Baker's geopolitically charged mission.
Bernini was courtly enough to dine regularly with the Pope, yet he had a Caravaggesque turbulence; once he had to be restrained from trying to kill his own brother. The reason his religious art is so impassioned is that it, too, was personal - he was not a hackish servant of Counter-Reformation policy but a devout member of a lay Jesuit order, who believed in and practised the passionate, dramatic, personal Catholicism identified with the Counter- Reformation saints Ignatius Loyola and Teresa of Avila.
It's the sudden, embarrassing intimacy that makes Bernini's most famous sculpture, The Ecstasy of St Teresa, so disturbing. It is framed by a chapel Bernini designed - the Cornaro Chapel in Santa Maria della Vittoria, Rome - as a sublime religious theatre. Under a painted heaven, at the centre of a proscenium whose action is witnessed by sculpted members of the Cornaro family in stage boxes at the sides, St Teresa lies in ecstasy on a cloud. Above her, rays of gold light shoot straight down from heaven; an angel stands over her aiming a spear at her heart. She swoons, moans, is in a rapture - her robe is flowing, as fluid as water; it seems to melt, as if her entire body were dissolving.
When Salvador Dali pointed out the resemblance of Catholic images of saintly ecstasy to orgasm in his surrealist collage The Phenomenon of Ecstasy, he was being deliberately blasphemous. But when Bernini harnessed sexual abandon on behalf of the Catholic church 300 years earlier, he was being perfectly orthodox. Bernini's sculpture is a completely faithful visualisation of the Spanish saint's vision. She saw an angel hold aloft his spear and then plunge it into her heart again and again: "The pain was so severe that it made me utter several moans. The sweetness caused by this intense pain is so extreme that one cannot possibly wish it to cease, nor is one's soul content with anything but God."
It was exactly the myth the Counter-Reformation church needed in its attempt to win hearts away from the individualist practices of Protestantism: the burden of the Ecstasy of St Teresa was that a more personal relationship with God was available through perfect devotion to the Church.
Bernini himself believed he had that relationship. He planned his own deathbed scene in detail, and the reason his Ecstasy of St Teresa still induces a shudder - the reason it is not just funny - is that it is also about death.
Bernini's religious art makes the church he served seem organic, alive and sensual; and this goes for his architecture, too. Who else, charged with designing a square that would offer Romans and pilgrims an appropriate ritual approach toward's St Peter's, could have come up with that encircling piazza, still an unrivalled model of urban space. Bernini characterised its architecture as the embracing arms of the church, hugging the faithful, reaching out to encircle the unfaithful. Instead of classically authoritative straight arcaded sides, he defined the vast space with recessive curvaceous colonnades that enfold the square - creating a space that is dwarfing and yet warm. The scale and almost womb-like enclosure make the piazza feel like an entrance to heaven itself.
But then, throughout Bernini's Rome, you teeter on the brink of the fantastic. Bernini defined Rome as we experience it today: not just creating the city's supreme piazza but inventing the civic fountains that are the city's magical trademark.
In the Renaissance, the fountain was a delight for princes' gardens, a private pleasure. Bernini created a masterpiece of this kind in his early work, Neptune and Triton (c1620-1), which lorded it over a fishpond in Rome's Villa Montalto until 1786, when it was bought by an Englishman who sold it on. It can now be seen in the V&A.
Bernini democratised the fountain. He invented a new kind of visually compact, spectacular fountain to animate city squares. His Four Rivers fountain in Piazza Navona is an allegory of Papal power - the four rivers are the four quadrants of the globe offering loyalty to the Pope. Yet it is also a gift for the people, pouring fresh, cool water year round over fantastic artificially carved mountain outcrops, while over it all soars an Egyptian obelisk. Bernini said he loved water; looking at it made him happy. He turned it into the flowing symbolic lifeblood of Rome.
Bernini made the city a perpetually festive place, using fountains to make architecture move and live, as if, not content with making stone look alive, he wanted to sculpt in water. Today, we have the fountains to remind us of Bernini's lost, ephemeral theatre productions, which astonished contemporaries. In his theatrical production The Flooding of the Tiber, the nearby river suddenly burst its banks. Only when it magically drained away did the fleeing audience realise this was the "play".
Bernini was revolutionary - and our contemporary - in abandoning the Renaissance obsession with the various arts as being rivals, and instead seeing them as an ensemble. He practised a 17th-century version of installation art. His most extreme acts of theatre were carried out in the awesome surroundings of St Peter's - only he could think up altars and tombs stupendous enough to catch the eye under Michelangelo's mind-bending dome.
In the 20th century, Giorgio de Chirico created haunting paintings of Italian city squares as images of the psyche. Bernini, a man whose unconscious wells up and overflows in cascades of stone and water throughout the city he remade, was able to merge his own fantasies with public space. This is why his art is still so arresting, startling, and intensely pleasurable. Bernini has left us a self-portrait in the form of a dreamlike city.
