4 Sivan
In the Hebrew year 2448, Moses wrote the first part of the Torah, from Genesis up until the revelation at Mount Sinai. By the end of his life, Moses had written 13 Torah scrolls -- one for each tribe, and one more to place in the Ark of the Covenant. The existence of multiple scrolls in multiple locations ensured the integrity of the Torah text, as scrolls could be checked against one another for accuracy. Indeed, this method has continued for millennia, and Torah scrolls from Morocco to Russia, Australia to Iraq, all contain the same letter-for-letter text.
