Primary responsibility for the sculpture of the chapel belongs to Niccolò di Giovanni Fiorentino, Donatello’s pupil, and one of the major sculptors of the Italian Renaissance. In addition to sculptures by Alessi, Niccolò di Giovanni and Giovanni Dalmata, the chapel originally contained four statues by Alessandro Vittoria, which were banished to the bell tower, when windows replaced the niches housing them in the 17th century. In its iconography the Orsini Chapel reflects the chapel, no longer extant, of the patron of Zadar, St. Simeon, built next to the Church of St. Mary the Great in that Dalmatian city. The form of the Orsini Chapel, however, was inspired by a work of classical antiquity, the Temple of Jupiter, within the complex of Diocletian’s Palace in Split. All architectural and sculptural elements in the chapel are carved from a local limestone, which was famous even in antiquity for its excellent quality. White in its natural state, it became sooty with grime and candle grease over time.
Happily, structural problems in the roof had recently been solved by the Croatian Superintendency and therefore Venetian Heritage concentrated upon the cleaning and conservation of the stone in its myriad guises. This restoration, based on scientific research and involving international co-operation, was awarded the European Union prize for Cultural Heritage / Europa Nostra award 2003 for its high quality.