Giorgione – or Zorzi da Castelfranco, as he was known in Venice – was the phantom genius of Italian painting during the early 16th century, contemporary with an elderly Giovanni Bellini and a youthful Titian. During his brief existence (he died of plague in 1510, aged 33) almost nothing was known of him beyond the reality of an astounding talent. While praising Giorgione’s contribution to a “modern manner” alongside those of Leonardo and Raphael in his Lives of the Artists, Giorgio Vasari had little of genuine substance to draw on for a biography. This semi-mythical figure gathered such a host of attributions that by 1850 his name was attached to more than 300 paintings. Since then critical scrutiny has reduced these to a mere 40, a good few of them still the subject of vigorous scholarly dispute. A monographic exhibition is therefore nowadays unlikely. Instead, we have In the Age of Giorgione, devised by the Royal Academy’s Per Rumberg, working with curators from Bergamo and Florence, so as to embrace Giorgione’s artistic impact on the wider Italian milieu in which he worked. In this Renaissance context, influences from beyond the Alps form a crucial background element in many of the canvases exhibited here. A numinous presence in the exhibition, alongside Giorgione himself, is that of the young Albrecht Dürer, whose prodigious gifts were vitalised by two visits to Venice. His absorption with landscape, in a view of a watermill which includes himself busily sketching, is matched by Giorgione’s own passion for rocks and trees, crag-perching castles and shimmering blue distances. In the Uffizi’s Trial Of Moses or the enigmatic National Gallery’s Tramonto, nature is a dominant voice rather than a decorative undertone. The sense of Giorgione as a restless innovator, daring others to follow his lead, receives potent emphasis among the portraits in the show. From Antonio Brocardo’s pensive downward gaze to La Vecchia, with her bleary eyes and sagging mouth, the painter looks beyond his sitter as a static icon, probing deeper into solitude and secrecy. Others took up his challenge, including Titian in his Boy with a Pipe, or the positively menacing likeness of a gimlet-eyed man gripping a money bag. Even Pordenone’s Christ Carrying the Cross creates an arresting personal moment as opposed to a sacred image pure and simple. The game of attribution is played out amid a dazzling array of altarpieces. Is the Bellini really his? What makes a Sebastiano del Piombo not quite the genuine article? A buxom St Agatha and shadowy Judith from the unfamiliar hand of Giovanni Cariani make us long to know him better. The whole Academy show is a superb tribute to that “something fabulous and illusive” which Walter Pater detected in Giorgione – working its enchantments as powerfully on us as on the painters of his own time. Jonathan Keates is chairman of the Venice In Peril Fund