Rabbi Jacob ben Meir (Rabbenu Tam)

Rabbi Jacob ben Meir, known as Rabbenu Tam (c. 1100 - 4 Tammuz 4931 / June 9, 1171), was the foremost of the Ba'alei HaTosafot, a Talmud commentator and one of the greatest halakhic decisors among the Rishonim. A grandson of Rashi and son of Rabbi Meir of Ramerupt, he lived in 12th-century France and was considered the greatest sage of French and Ashkenazi Jewry in his lifetime. He authored 'Sefer HaYashar' and a book on Hebrew grammar, and was also known as a poet and grammarian. His nickname 'Rabbenu Tam' is derived from the verse 'and Jacob was a tam (plain) man, dwelling in tents' (Genesis 25:27).

Rabbenu Tam is considered one of the greatest Rishonim and the head of the Ba'alei HaTosafot. His method of study, characterized by precision and sharpness, became the basis for Talmud study in all yeshivot to this day. His commentaries and innovations, incorporated into the Tosafot, are inseparable from any Talmud study. His book 'Sefer HaYashar' is a foundational document in halakhic ruling, and his decisions were adopted as law in the Shulchan Arukh and by many poskim. His students spread his Torah throughout Europe, and produced generations of sages who continued his path. His works on grammar and piyyut also influenced generations. The figure of Rabbenu Tam became a symbol of greatness in Torah, of fear of Heaven, and of the combination of wisdom with wealth and action.