che sona di clevo’ (without an attribution) which was sold together with Caravaggio's St Catherine and the Cardsharps (named specifically as by Caravaggio) and various other paintings to Cardinal Antonio Barberini, which has come down to us in the work in the Wildenstein collection. The flowerpiece is of major importance for the still-life tradition, not only in Italy, but also in the Netherlands, and there is a certain link to earlier Flemish painting; for example, many of the Flemish flower painters, from Jan Brueghel to Ambrosius Bosschaert and Van der Ast, often waited to study separate specimens in various seasons of the year but include them all in a fictive assembly. The fruits in the Luteplayer, however, are not of the same season as the flowers, suggesting a similar cross-seasonal approach as Brueghel and Bosschaert. The flowers correspond with those illustrated by Giovanni Battista della Porta in his Magia Naturale (Naples, 1589) as ones corresponding to vision, from the marigold that looks like the Sun, the yellow cornflower that looks like the eye, to another flower that resembles the eyebright that was since the Middle Ages an ingredient in eye remedies. This would go some way to explaining the nature of the choice of the flowers, which are dominated by the irises at the top, and Iris was not only the messenger of the gods, but in the optical frame stood for the rainbow and the spectrum of colours that the various flowers represent. Once again, Della Porta's De refractione optices has an entire book devoted to ‘De Iride et colore’, an attempt to arrive at an understanding of the rainbow. But the naturalism of the flowers, including the seedpods of the iris and the shrivelled florets, shows that Caravaggio was observing these from actual specimens, and not improving on what Nature might have arrived at had circumstances been different. The tacit expression of the theory of segnatura, the correspondence of certain forms from the natural world with those in man, is something that links the thinking behind the painting with Paracelsian belief. Del Monte's interest in this is manifest in the group of portraits that hung in his alchemical Casino, which are of the same seven luminaries who are illustrated in the titlepage of Oswald Croll's Basilica Chymica (Frankfurt, 1609). We know that the Casino on the Pincio was the centre in Rome of the practice of iatrochymia or