LUNETTA. — Architecturally, l. denotes the space resulting from the intersection of a vault with a plane surface; thus, in a room covered by a groined vault, a sail vault, or a barrel vault with lunettes, l. are the spaces between one springing point and another. Depending on the arch that generates it, the l. may be semicircular, pointed, or segmental.
From the earliest Christian period onward, the pictorial decoration of l. is extremely frequent: in fresco (the cubicula of the catacombs), in mosaic (the mausoleum of Galla Placidia and S. Vitale in Ravenna), and in inlay (the Baptistery of the Orthodox, also in Ravenna). The decoration of l. in atria and, above all, in cloisters lent itself to cyclical representations; famous examples survive from the Quattrocento onward (the Green Cloister of S. Maria Novella in Florence, by Paolo Uccello; the Chiostrino dei Voti of the Annunziata, by A. Baldovinetti, A. del Sarto, Franciabigio, Pontormo, and Rosso; the cloister of the charterhouse of Val d'Ema, by Pontormo, etc.); for the most part, episodes from the lives of saints of the Order to which the church belongs are represented (the cloister of Monteoliveto near Siena, with Storie di s. Benedetto, by Signorelli and Sodoma; the cloister of S. Marco in Florence, with Storie di s. Antonino, by Pocetti).
The name l. is also given to the space above a door, between the arch and the architrave, and hence to the carved panel that often constitutes its decoration, and generally to any semicircular carved panel. L. of portals and bas-reliefs are found in the Romanesque period (13th century: S. Zeno in Verona, S. Clemente at Casuria; 13th century: the parish church of Arezzo, the Baptistery of Parma, the cathedral of Lucca, etc.) and even more frequently in the Trecento (the cathedral of Lucca, Deposizione, attributed to Nicola Pisano; S. Martino in Pisa, attributed to Andrea da Pontedera). Among the innumerable examples of the Renaissance, mention should be made of the chromatic innovation introduced by Luca della Robbia with his white and polychrome glazed-terra-cotta l.
Finally, l. is also the name given to the semicircular crowning of altarpieces, in use during the second half of the Quattrocento, especially in northern Italy, and almost always depicting the Pietà (Cosmè Tura, Louvre; Crivelli, Brera and the Pinacoteca Vaticana; Lotto, S. Cristina near Treviso, etc.).