ראב"ן

Rav Eliezer ben Nathan of Mainz (c. 4850/1090–4930/1170), the Raavan, was among the earliest of the Baalei Tosafot in Ashkenaz. He was the son-in-law of Rav Elyakim ben Yosef of Mainz, a talmid chaver of Rashi, and headed a yeshiva in Germany. He corresponded with Rav Meir ben Shmuel, with Rabbeinu Tam, and with the Rashbam, and signed communal takkanot together with them. Through his four daughters he became the forebear of learned families for generations; his grandson and talmid was the Ra’avyah, and the Rosh, Rav Asher ben Yechiel, traced his own descent to him.

The First Crusade fell in his childhood, and in its wake he composed kinot and selichot on the gezerot of 4856, along with a chronicle of the persecutions of that year — a record set down in order, giving voice to grief and wrestling with how such slaughter of Jews could come to be. Some twenty-five of his piyyutim are known, a number of them written for particular occasions such as a bris.

His Even haEzer, also called Tzafnat Paneach and known simply as Sefer Raavan: a collection of responsa and halachic decisions arranged as a commentary running through the Bavli, which he assembled from smaller topical pamphlets. Its aim was to show that the customs of Ashkenaz, resting in good part on Eretz-Yisrael sources such as the Pesikta, accord with the Bavli and do not contradict it; he was the first of the German authorities to bring the commentary of Rabbeinu Chananel. The work mentions the year 1152 and was completed after it, yet it stayed little known until the leading rabbis of Poland — among them Rav Mordechai Yaffe, the Maharsha, and Rav Shlomo Ephraim of Luntschitz — pressed for its printing in an appeal from Posen in 5369/1609; it appeared from manuscript in Prague the following year.