Robert Jonas was born in 1883 in Vienna, the son of Benjamin Jonas and his wife Flora, née Spitzer, from Ballasa-Gyarmat in northern Hungary. He completed his studies in 1904 at the Niedere und Höhere Fachschule at the k. k. Technischen Gewerbemuseum (Imperial Royal Applied Technology Museum) in Vienna. In 1905/06 he attended two courses at the Vienna University of Technology. In subsequent years he was no longer registered as a student. In 1906 he converted from Judaism to Protestantism and married Marianne Weiss on 5 August 1918. They had two children, Lili Marietta and Peter Julius, both of whom were baptized as Protestants. The family lived with Marianne's parents Julius and Berta at Dittesgasse 40 in the 18th district, and then from 1935 at Gustav-Tschermak-Gasse 14. After the annexation of Austria to the German Reich, the Jonas family, who were regarded as Jews in the meaning of the Nuremberg Laws, were subject to persecution. In his asset declaration, Robert Jonas stated that he was the manager of an Austrian Brown-Boveri factory. In autumn 1938, the family managed to escape to Switzerland. In 1941, pursuant to the Elfte Verordnung zum Reichsbürgergesetz (Eleventh Regulation on the Reich Citizenship Law) of 1941, the Nazi authorities expropriated their house and savings and stripped them of their citizenship. A short time after the deportation of Marianne's mother to Litzmannstadt ghetto in 1941, Obersturmbannführer Alois Brunner, head of the Zentralstelle für jüdische Auswanderung (Central Office for Jewish Emigration) and hence instrumental in the deportation of Jews from Vienna to concentration and extermination camps, moved into their apartment. The Jonas family never returned to Austria. Robert Jonas died in 1952 at the age of sixty-nine.
In 1938, the Volkskundemuseum Wien (Museum of Folk Life and Folk Art Vienna) purchased a plywood box, ceramic jug and plate from Robert Jonas for 130 Reichsmarks. In view of their historical and ethnological interest, the two ceramic objects were displayed for several years in Schloss Gobelsburg and in the permanent exhibition of the Museum of Folk Life and Folk Art Vienna. It was only during the digitization of the objects in the museum database and the systematic provenance research that the objects acquired from Robert Jonas came under suspicion in the meaning of the Art Restitution Act. In 2017 the Art Restitution Advisory Board recommended their restitution to the legal successors of Robert Jonas, and they were returned in May 2019.
Based on research by Claudia Spring.