Machzor Vitry contains decisions and rules concerning religious practise, besides responsa by Rashi and other authorities, both contemporary and earlier.
Isaac ben Samuel, a grandson of Simchah, also refers[1] to Machzor Vitry compiled by his grandfather.
Various additions were afterward made to this machzor, a large proportion of which, designated by the letter ת' (= "tosafot"), are by Isaac ben Dorbolo.
The latter often appends his name to such additions; and in one place he says plainly: "These explanations were added by me, Isaac b. Dorbolo; but the following is from the Machzor of R. Simchah of Vitry himself".
[2] Other additions are by Abraham ben Nathan, author of Ha-Manhig, and are designated by the letters אב"ן, his initials.
Several manuscripts of Machzor Vitry are extant, the oldest of which, according to Abraham Berliner[3] is from Isaac Samuel Reggio, currently in the Jewish Theological Seminary of America library (NY JTS 8092).
1100), is said to have marginal annotations by Eleazar ben Judah, author of the Sefer ha-Rokeach (Michael, Or ha-Chayim.
27,200 and 27,201), and contains still other additions; this manuscript served as basis for S. Hurwitz's edition of Machzor Vitry published by the Meḳiẓe Nirdamim Society (Berlin, 1893).
The edition is very faulty, as the editor used no critical judgment in his work; instead of the original treatises it contains some from the Sefer ha-Terumah of Baruch ben Isaac and from the Eshkol of Ravad.
In the published edition of this Machzor there is also a commentary on the Pesach Haggadah, which, however, does not agree with that by R. Simchah b. Samuel of Vitry printed at Vilna in 1886.
Likewise there are found in Machzor Vitry citations from the Jerusalem Talmud which are lacking in the existing editions of the latter.