NICCOLÒ DI SER SOZZO
(d. 1363, Siena)
Manuscript, 436 x 305 mm
Archivio di Stato, Palazzo Piccolomini, Siena
The Caleffo is a copy of an official act of a municipality, kept separately from the originals to be able to have on hand. This name, of uncertain etymology, was used in Siena in the Middle Ages. Because of this full-page and brightly coloured image of the Virgin in Assumption, the present manuscript is almost exclusively referred to as the Caleffo dell'Assunta. The frontispiece of the manuscript was, for a time, the defining work attributed to its illuminator, Niccolo di Ser Sozzo. This illumination has much in common with Sienes masterworks like Simone Martini's Maesta or Ambrogio Lorenzetti's Allegory of Good and Bad Government.
The picture shows an illuminated page of the Caleffo dell'Assunta. The illumination, made by Niccolò di Ser Sozzo, a skilled painter having expertise specialised in the production of manuscripts, represents the Virgin of the Assumption with St Thomas receiving the girdle, and Sts Crescenzio, Victor, Savino and Ansano.