The Arab inhabitants used a north-south division of Arabia: Al Sham-Al Yaman, or Arabia Deserta-Arabia Felix. Arabia Felix had originally been used for the whole peninsula, and at other times only for the southern region. Because its use became limited to the south, the whole peninsula was simply called Arabia. Arabia Deserta was the entire desert region extending north from Arabia Felix to Palmyra and the Euphrates, including all the area between Pelusium on the Nile and Babylon. This area was also called Arabia and not sharply distinguished from the peninsula.