Rav Yitzchok Ba'al Hatosfos, Ri Hazokein (Tishrei 27, 4950 / 1189 - 835th Yahrzeit)
Rav Yitzchok was the son of Rav Shmuel and grandson of Rav Simcha, mechaber of Machzor Vitri and a talmid of Rashi.
His mother was the sister of Rabbeinu Tam, Rashbam, and Rivam, the grandsons of Rashi. Rav Yitzchok succeeded Rabbeinu Tam in Romberg.
The Seder HaDoros writes that Rav Yitzchok HaZoken had sixty talmidim, each one a Rav who heard the halocha that he taught, and who also each studied a separate mesechta on his own that his fellow students did not learn. He would study that mesechta by heart and repeat it from memory.
Rav Yitzchok only taught halocha once every talmid had answered all the doubts, questions, and difficulties arising from the Gemora he had studied. Each halocha that appeared to contradict another source in the Gemora would be analyzed until it too was answered and corrected.
The Maharshal wrote that Rav Yitzchok HaZoken’s talmidim were: Rav Moshe HaKohen Ashkenazi, Rabbeinu Ezra HaNosi, Rabbeinu Shimshon of Nevelya, Rabbeinu Shimshon of Shantz and his brother Rav Yitzchok, and Rabbeinu Boruch, mechaber of Sefer HaTerumos. The Seder HaDoros adds to this list Rabbeinu Shimshon of Kotzi (Caucy) and Rabbeinu Shlomo of Droise.
Elsewhere we are told that Rabbeinu Yehuda of Paris, mechaber of Sefer HaKovod, who led after Rabbeinu Yitzchok HaZoken, was also previously one of his talmidim; others say that Rav Yitzchok of Dampierre, cited by the Rishonim, is the very same Rav Yitzchok HaZoken, grandson of Rashi’s daughter (others say that they are not the same person).
Most of the great Ba’alei Tosfos were Rabbeinu Yitzchok HaZoken’s talmidim. They ruled like him even against Rabbeinu Tam, who was Rabbeinu Yitzchok HaZoken’s Rebbe.
The Gedolim of his generation considered him a true posek and they thirstily drank up the waters of his wellspring; many nicknamed him Rabbeinu HaKodosh.
He had two sons who were Gedolei HaDor: Rabbeinu Elchonon Ba’al HaTosfos HY”D, who was killed in 4544, and Rabbeinu Shlomo, who was niftar at a young age in 4531.
Rabbeinu Yitzchok lived a long life and was niftar on 27 Tishrei at the end of the fifth century. Some say he lived until the beginning of the sixth century.
