Machzor Vitry is an 11th-century prayer book that incorporates legal rulings, composed by Rabbi Simcha of Vitry, a French scholar and disciple of Rashi. The word “machzor” (cycle) signifies that in addition to daily prayers, the book includes prayers for unique days on the Jewish calendar, like Shabbat, holidays, and fast days. Also incorporated are commentary on the Ten Commandments and Pirkei Avot, liturgical poems, descriptions of messianic times, and legal sections on marriage, holidays, and ritual slaughter, among other topics. The work incorporates many of Rashi’s decisions as well as decisions of other major authorities and is considered a critical source of French liturgy traditions.