Organ shutters, used in large organs for acoustical and aesthetic reasons, offer a two-fold interest to the art historian: iconography and style. Iconographically, many organ shutters in all periods displayed the Annunciation when closed. Images of the saints might be on the exterior or interior of the organ shutters; and the iconography evolved from simple devotional images of patron saints in ca. 1450, through narrative, historical images of patron saints in ca. 1520, to complicated combinations of themes from the Old and the New Testament in the entire sixteenth century. Stylistically, organ-shutter painters tried, from the very beginning, to break down the barrier between the pictorial plane of the organ shutters and the real space of the spectator; accordingly, two kinds of perspectival devices were used: the dal-sotto-in-su was usually used for the exterior, the eyelevel for the interior. Therefore, organ-shutter paintings are more than mere reflections of the contemporary artistic trends; a separate tradition evolved for organ-shutter perspectives. However, two styles - Manerism and Classicism - coexisted and rivalled each other, not unlike what was happening concurrently in frescoes or in easel paintings. These two styles achieved their apogee simultaneously in organ-shutter painting between 1550 and 1570. In these years Mannerism was represented by Jacopo Tintoretto, and Classicism by Paolo Veronese.