Yemenite scrolls of the Law containing the Five Books of Moses (the Torah) represent one of three authoritative scribal traditions for the transmission of the Torah, the other two being the Ashkenazi and Sephardic traditions that slightly differ. While all three traditions purport to follow the Masoretic traditions of Aaron ben Moses ben Asher, slight differences between the three major traditions have developed over the years. Biblical texts proofread by ben Asher survive in two extant codices (the Aleppo Codex and the Leningrad Codex), the latter said to have only been patterned after texts proofread by Ben Asher. The former work, although more precise, was partially lost following its removal from Aleppo in 1947.