The Italian Renaissance was an age of nomads. Wandering painters, sculptors and workers in precious metals toted their technical skills from one city or court to another, perfectly ready to roll up a canvas, pack a painted panel or wrap a marble bust to be transported long distances down roads, rivers and canals. Everything, it might have seemed, was against them: regime change and warfare in the various duchies and city states, visitations of the plague, exorbitant demands of customs officials, floods, avalanches, brigandage and piracy. The point was to keep moving. Art, like spices, sugar and silk, was a marketable commodity, its value enhanced by the publicity fostered through the new invention of printing and the evolution of specialised forms of diplomacy in which artists themselves could play a part.

Take the case of Bernardino di Betto from Perugia, known to the art world by his nickname Pintoricchio. Ever since Giorgio Vasari in his Lives of the Artists sneered at the painter as a mere chancer who never deserved his good luck, critical orthodoxy has rated him little better than a fancy ecclesiastical interior decorator. For many of us, however, he consistently enchants through his handling of colour, detail and design. Feeling crowded out of his native city by his compatriot Perugino and the young Raphael, Pintoricchio set off for Rome, where he cornered the fresco market under the patronage of three popes in a row. The last of these, Pius III, was pontiff for only twenty-six days. However, in that short time he managed to commission the wondrous Piccolomini Library cycle in Siena, glorifying his uncle Aeneas Sylvius, who, after a colourful career as a traveller, novelist and lover, became Pope Pius II and died while launching a crusade against the Turks.

Pintoricchio was a shrewd operator, buying farms and fields to bolster his status in Perugia, and was happy to work as a frescante errante. He rounded up teams of local artists wherever he happened to be and trained them to execute his basic pictorial schemes, so that he could drop