R. Jacob b. Shlomo ibn Habib (?1445–1515/16), was born in Zamora in Castile, Spain, where he is said to have been a pupil of R. Samuel Valency, and was one of the renowned scholars of Castile, heading a yeshivah in Salamanca which was one of the largest in Spain. On the expulsion of the Jews from Spain in 1492 he went to Portugal and before 1501 proceeded to Salonika where he became one of the leading scholars. First he taught in the Calabrian (native) community, and later was appointed rabbi of the Gerush community (of Spanish exiles), a position which he held until his death. His name appears among the first signatories on the early regulations of Salonika. He was personally responsible for some of these regulations, which would even seem to have been formulated by him. He also conducted a yeshivah in Salonika. His contemporaries and successors spoke of him in terms of the highest esteem and referred to him as gedol ha-dor ("the greatest of the generation"), mofet ha-dor ("the wonder of the generation"), and ha-ga'on. Individual responsa by him have been preserved in the works of contemporary and later scholars (R. Elijah Mizrahi, R. Samuel de Medina, and in the collection of responsa Zera Anashim (1902), while others exist in manuscript. He is quoted at length in the works of the great scholars of the period (R. David b. Hayyim ha-Kohen of Corfu, R. Joseph Caro, R. Joseph ibn Lev, and others). Remnants of his halakhic works have also been preserved. In his Beit Yosef, R. Joseph Caro gives quotations from R. Jacob's commentary on the beginning of Orah Hayyim and the beginning of Yoreh De'ah of the Arba'ah Turim. R. Samuel de Medina in his responsa (YD, 44) gives a synopsis of his article on the law of terefah, and there are references to disputes between him and his contemporaries on halakhic topics. His extant responsa show his special concern with the problems that occupied the generation after the expulsion - such as the case of a childless widow whose brother-in-law, from whom she had to receive halizah, had become converted to Christianity - as well as the new problems which had arisen as a result of the settling of the Jews of Spain in places where the religious customs (minhag) differed from those in vogue in Spain. R. Jacob took up a tolerant attitude toward the customs of these communities and their scholars and accepted compromises, instead of forcing his views upon them, as did the scholars of the following generation. He states explicitly that he had not studied philosophy and the sciences methodically, although he had occupied himself with these subjects in his youth. His knowledge of Kabbalah, toward which he took a positive attitude, was also the result of casual reading.

הסכמות: ר' דוד ב"ר אברהם אופנהיים מפראג, ווינא, כו אלול תס"ז; - חלק א ר' נפתלי הכהן, פרנקבורט דמיין, כו שבט תס"ח; - חלק א ר' גבריאל ב"ר יהודא ליב [עשקעלעס] מקראקא, נ"ש (ניקלשפורג), י אייר תס"ז; - חלק א ר' יששכר בערמן ב"ר דוד יצחק זעקיל סג"ל [פרענקיל], פירדא "ורובץ תחת משא בני מדינות אנשבך וק"ק שנייטך", א דראש-חודש אדר תס"ח; - חלק א ר' שמעי' ב"ר אברהם יששכר בער מברלין, "פרנקפורט ביומא דשוקא", כב [צ"ל: כד] אדר תס"ח; - חלק א ר' אהרן ב"ר יצחק בנימן וואלף, ברלין "ומצ"פ בק"ק פרנקפורט דאדר", ערב ראש-חודש אב תס"ט; - חלק א ר' יהודא אריה ליב, אמשטרדם, ו אב תס"ח; - חלק א דייני אמשטרדם: ר' יהודא ליב ב"ר אפרים אשר אנשיל המבורג שפץ , ר' יצחק ב"ר שלמה מזאמשטש, ר' יוסף ב"ר ראובן יהודא כ"ץ ור' פנחס זעליג ב"ר משה, "זעירא דחברייא דבני ישיבה דק"ק פוזנן ... ספרא ודיינא דק"ק אמשטרדם", ערב ראש-חודש מרחשון תס"ח. - חלק א ב: ר' יהודא ליב ב"ר משה, גלוגא רבתי, לו למב"י [כא אייר] תס"ח; - [חלק ב] ר' אברהם מרדכי ב"ר ישראל היילפרן מוואלטש, פרנקפורט דאדר, כד תמוז תס"ז; - [חלק ב] ר' סעדישעיה [סעדיה ישעיה] ב"ר שאול לבית קצנאילנבוגין, מעזריטש, בא תס"ח; - [חלק ב] רבני פוזנן: ר' שמואל זנבל ב"ר חנוך, ר' יצחק ב"ר מאיר "פרנס ראשון וב"י [ונאמן בית ישראל]", ר' פלק ב"ר מאיר דרשן ור' יעקב ב"ר מאיר "דיין וב"י", טז שבט תס"ח. - [חלק ב]