Isaac ben Samuel of Dampierre (Ri HaZaken)

One of the foremost tosafists, frequently quoted throughout the pages of the tosafot commentaries on the Talmud. On his father's side he was a grandson of R. Simchah ben Samuel of Vitry, author of the Machzor Vitry. And on his mother's side, he was a great-grandson of Rashi and a nephew of Rabbeinu Tam, Rashbam, and Rivam. He was surnamed "HaZaken" (the elder) to distinguish him from his disciple, Isaac ben Abraham "HaBachur" (the younger), also a Tosafist.