This blog post is the first time I've ever heard someone suggest that the Hebrew Torah was written so recently. It should be noted that Leviticus is part of the Torah, parts of which are included in the Bible but predate the Bible as we know it by several centuries.

The oral tradition of the Torah is even older than the written version, possibly even older than the Greeks themselves (though I'm no historian, so I don't cling to that idea stubbornly.)