The small Belgian town of Mechelen is a quiet place. It grew rich on wool and once made the finest lace in Europe, but it's not hard to guess that the main attraction for many residents these days is its proximity to Brussels, just 20 minutes away by commuter train.  The neat streets are studded, however, with a number of startlingly grand buildings, dating from the glory days – the decades in the late 15th and early 16th century when the town was the heart of the territory of the powerful Dukes of Burgundy, who had long since expanded northwards to control an area that stretched from Switzerland to the North Sea.  It was also the home of an extraordinary artist: Jan Gossaert. Nearly 500 years on, Gossaert's paintings – now scattered in major collections across the world – are being assembled for a major exhibition of a man who was a star of his day, widely imitated by his contemporaries, and regarded by art historians as a crucial bridge between the Renaissance Italian style and the dazzling medieval oil painting of the north.  "When I stand in a room full of his paintings, the sheer quality of the work is overwhelming," says Susan Foister, director of collections at the National Gallery, the woman who is curating the show at London's National Gallery. "His technique is extraordinary: the way he paints textures, so you feel every strand of fur, every hair. He is undoubtedly one of the giants."  Yet for a painter of such talent, Gossaert's name is far less familiar than his great Flemish predecessor Jan van Eyck, or Peter Paul Rubens a century later. And when the new exhibition – shared with the Metropolitan Museum in New York – opens this week, it will be the first occasion in a lifetime that a show of this nature has appeared on these shores. It is a measure of the artist's elusiveness that the two institutions can't even agree on his name (in London he will be Gossaert, in Manhattan Gossart).  As it happens, you won't find either in older art histories, which call the artist Jan Mabuse after Maubeuge, the town (now in France) where he was probably born in 1478. He signed his 1516 painting Neptune and Amphitrite, now in Berlin, "Joannes Malbodius". He is probably also the "Jan of Hainault" who was enrolled in the Antwerp painter's guild in 1503, and was also sometimes known as Jennyn van Hennegouwe.  What Gossaert looked like is equally mysterious. The only full-face portrait, an engraving in a 16th-century book on Flemish artists, may not be remotely accurate since it was made from a profile medallion: it shows a rather grave figure, a long bearded solemn face, under an elaborate hat. And, tormentingly, there are only a handful of anecdotes about his life. Karel van Mander, a painter who published a book of biographical sketches of northern artists inspired by Giorgio Vasari's wonderfully gossipy tales, says Gossaert made and wore a painted paper robe for a state reception for the Holy Roman Emperor Charles V, presumably to show off his trompe l'oeil virtuosity. "And when the Marquis, as they passed by, asked the Emperor which damask he thought the most beautiful," Van Mander wrote, "the Emperor had his eye on that of the painter which – being very white and beautifully decorated with flowers – far excelled all the others." Charles reportedly had to touch the fabric to believe it was painted paper.  Gossaert certainly knew the work of his slightly younger contemporary, the German Albrecht Dürer; and Dürer knew of him. However, it seems that they never met in person, even though Dürer made a special trip to see one of Gossaert's works in 1520, an altar piece at a church in Middelburg (now in Holland). He merely recorded laconically that the deposition from the cross was "not so good in its main lines as in the painting"; we can't check Dürer's assessment because the painting was destroyed in a fire just 30 years later.  So why has Gossaert come into focus once again? Partly because he was an innovator. Thomas Campbell and Nicholas Penny, co-directors of the exhibition, argue for his "intense originality" as an artist – an originality that will be fully on view. Unlike earlier Adams and Eves, Gossaert's nude figures were blatantly secular, but nonetheless full of references which would have been picked up immediately by an educated audience. One of the paintings in the exhibition is Hercules and Deianeira (1517), the couple's legs uncomfortably intertwined, perched on a stone bench carved with a classical frieze – a clear gesture to Roman architecture and Greek philosophy, and of the new humanist philosophy which was sweeping across Europe. The Burgundians recognised that originality, and various members of the family were Gossaert's main patrons for decades. The dukes were avid for art, seeing it – as the Medici did in Italy – as an outward manifestation not just of immense wealth, but of their culture and learning.  Gossaert suited them to perfection. His classical nude of Danae, on loan to the exhibition from the Alte Pinakothek in Munich, now seems unremarkable, but in 1527 the work must have looked astonishing: an unarguably erotic figure gazing up with dreaming eyes and parted lips at the shower of gold falling into her lap, her gown falling from her shoulders to reveal one breast. It features a detail contemporaries would not have missed: her gown is a vivid, clear blue, one of the most expensive pigments of the day, which was traditionally reserved for the robes of the Madonna.  Many of these references were gleaned from a trip the artist made to Rome in 1508, a highlight of his career, and also a major event in the history of European art. A century before Rubens, Gossaert became the first Flemish artist to bring back the style of Raphael and Michelangelo to the studios of the north. He went there as court artist to Philip of Burgundy, who was an exceptionally secular bishop, the illegitimate son of Philip the Good, an admiral and a diplomat as well as a churchman whose palace was decorated with erotic art. Philip sent Gossaert to draw the half-ruined ancient monuments and buildings and newly excavated classical statues, as well as the new works they inspired.  His drawings reveal exactly what the artist came across. One sheet in the exhibition, on loan from a collection in Leiden, has on a single page a beautiful drawing of a famous Roman bronze, the Spinario, a graceful boy picking a thorn out of his foot. Gossaert has also crammed in two fancy parade helmets; a lion's head and a broken lion mask which he may have seen on stone coffins in the Forum; a slender leg in a laced boot; and a heavily muscled leg in a ludicrously elaborate open-toed boot which has been traced to a colossal statue excavated from the Baths of Caracalla. He mined his Roman drawings for figures and classical ornament for the rest of his working life.  The new exhibition will also show his wonderful portraits, including his canny young merchant of 1530, on loan from the National Gallery in Washington, framed by stacks of invoices, painted in minute detail down to the slightly grubby nails of his fingers.  Why, then, has Gossaert been neglected for so long? Foister suggests that he partly fell out of public consciousness because the works were so widely scattered, and because many of the panel paintings were too vulnerable to travel. "Because there were no major exhibitions, there have been few recent major studies of his work," she argues. "The catalogue for this exhibition, a major work of scholarship, should go a long way to redress that."  Not that the fresh scrutiny has come free of problems – in the course of research, questions have been raised over the true authorship of the gallery's Adoration of the Magi, a spectacular work which has long been one of the gallery's most popular Christmas cards, with the three sumptuously dressed kings presenting magnificent golden gifts.  "I stand by our picture," Foister insists. "I still think it is Gossaert. But that's exactly what this exhibition is for, to raise as many questions as possible about Gossaert – and, if possible, answer some of them."  Maev Kennedy travelled in Flanders courtesy of Tourism Flanders.
He may not be a household name, and his life is shrouded in mystery – but Jan Gossaert's paintings are among the most extraordinary creations of the northern Renaissance. Maev Kennedy travels to Flanders to find out more