The bottom line is that for Wellhausen and many other biblical scholars before and since, the Pentateuch as we know it (an important qualification) was not completed until the postexilic period (after the Israelites were allowed to return to their homeland from Babylon beginning in 539 BC). There were certainly long-standing written documents and oral traditions that the postexilic Israelites drew upon, which biblical scholars continue to discuss vigorously, but the Pentateuch as we know it was formed as a response to the Babylonian exile. The specifics of Wellhausen's work no longer dominate the academic landscape, but the postexilic setting for the Pentateuch is the dominant view among biblical scholars today.