Background
He was the grandson of Rashi, and brother of the Rashbam and the Rabbeinu Tam.
He was the grandson of Rashi, and brother of the Rashbam and the Rabbeinu Tam.
His father was Meir ben Samuel and his mother was Yocheved, the daughter of Rashi. He died before his father, leaving four children. Although he died young, the Rivam contributed to Tosafos, mentioned by Eliezer ben Joel HaLevi (Abi ha-"Ezri, 417), to several tractates of the Talmud.
Isaac himself is often quoted in the edited Tosafos (Shab 138a.
Ket 29b et passim).