SONNE, ISAIAH (1887–1960), scholar, historian, and bibliographer. Born in Galicia, Sonne studied at Swiss and Italian universities and at the Collegio Rabbinico in Florence, where he later became a lecturer in Talmud, philosophy, and Jewish history after having taught at the Hebrew high school in Lodz. In Florence he also taught German in a state high school and worked in the libraries and archives of the Jewish communities in Italy. From 1936 to 1939 he headed the rabbinical seminary in Rhodes, and in 1940 became lecturer and librarian at Hebrew Union College, Cincinnati.
Sonne's scholarly interests extended to history, particularly that of Italian Jewry; biography (Judah Abrabanel, Uriel d'Acosta, Leone Modena); philosophy (Spinoza, Pascal); Hebrew literature (Immanuel of Rome); bibliography; and Jewish art. He was a scholar of penetrating insights, able to extract underlying historical theories from seemingly trivial details, e.g., his article in the Alexander Marx Jubilee Volume (1950, Hebrew section, 209–32). Sonne discovered a number of hitherto unknown works and documents, his main work consisting of articles that he published in learned periodicals and Festschriften. His books include Avnei Binyan le-Toledot ha-Yehudim be-Italyah ("Documents in the History of the Jews in Italy," 1938–40) and Mi-Paulus ha-Revi'i ad Pius ha-Ḥamishi "From Paul iv to Pius v," 1954); among his bibliographical studies is his "Expurgation of Hebrew Books; the work of Jewish Scholars" (in: Bulletin of the New York Public Library, 46 (1942), 975–1013). Of a polemical bent, Sonne was involved in a number of scholarly controversies. He bequeathed his collection of books and manuscripts to the Ben-Zvi Institute, Jerusalem, which published a memorial volume in his name in 1961.
E.E. Urbach, in: Sefunot, 5 (1961), 11–16; N. Ben-Menahem, ibid., 17–25 (bibl.); A.M. Habermann, in: Haaretz (Dec. 30, 1960); A.S. Halkin, ibid. (July 28, 1960).