Rabbi at Sabbionetta; died 1536. He was a disciple of Nathaniel Trabotto, and is mentioned with respect by R. Meïr Katzenellenbogen. Azulai claims to have seen two volumes of his responsa—perhaps those referred to in "Magazin," ii. 16. MS. 911 in the Bodleian collection contains Diena's notes on V04p595001.jpg according to the Roman rite (Neubauer, "Cat." col. 196); and MS. 948 contains some of his letters (ib. col. 205). MSS. 48, 135, 153, 166 of the Friedland collection in St. Petersburg contain some of Diena's decisions. He seems to have possessed valuable manuscripts; the 1550 ed. of Maimonides' "Yad" having followed his copy (Conforte, "Ḳore ha-Dorot," p. 34b). Diena became known by his opposition to the adventurer David Reubeni. Being of a positive and practical disposition, opposed to the current Messianic vagaries, Diena was alive to the danger resulting therefrom, and he decided to act against Reubeni. When the latter, after the execution of Molko, had increased his influence to such an extent that the Italian rabbis began to take his pretensions seriously, Diena called to his aid Abraham b. Moses Cohen, rabbi of Bologna, and both unmasked the impostor.

The veneration in which Diena was held may be seen from the elegies published at his death, one of which was by Abraham of Pisa, and two others by Samuel b. Moses Anav. His son's name was David (Nepi-Ghirondi, "Toledot Gedole Yisrael," p. 75).