The name of Siviero is mainly linked with the work of tracking down Italian works of art that went missing during the Second World War. He was involved in tracing and returning to Italy those Italian works of art that had been illegally exported between the 1930s and 1980s.
During the Nazi occupation, Siviero worked as an agent for the Information Service which, under allied military command, collaborated with the anti-fascist forces and, whilst working for intelligence, he also gathered information on the stealing of works of art by the Nazis. After the liberation of Florence (August 1944) Siviero collaborated, on behalf of the Italian Ministry for Education, with the allied Commission Fine Arts and Monuments for the protection and return of Italian works of art. In April 1946 the Italian Government formally established an Office for recovering the works, directed by Siviero. In October of the same year he was posted as head of the Italian diplomatic mission to the Allied Military Government in Germany with the task of negotiating the return of the works of art deposited in the German collecting points. From the 50s until his death in 1983, Siviero was in charge of the Italian Foreign Office's Delegation for recovering stolen works of art from Germany as well as other countries. A gallery of photos shows some of the works saved by Siviero and tells their story.
The rescue of Fra Angelico's Annunciation The most important work of art saved by Siviero during the German occupation is Fra Angelico's Annunciation. The painting was originally kept in the Franciscan monastery of Montecarlo near San Giovanni Valdarno. At the beginning of 1944, Siviero's Information Service heard that Goering wanted the masterpiece for his own collection and that the Kunstschutz had been ordered to take the painting to Germany. Siviero turned to the Soprintendenza and two Franciscan Friars in Florence and the masterpiece was removed and hidden the day before the Germans arrived. The painting is now in the Museo della Basilica di Santa Maria delle Grazie in San Giovanni Valdarno.