Many historical periods in the Near East are named after the dominant political force at that time, such as the Akkadian or Ur III periods. This is not the case for the ED period. It is an archaeological division that does not reflect political developments, and it is based upon perceived changes in the archaeological record, e.g. pottery and glyptics. This is because the political history of the ED is unknown for most of its duration. As with the archaeological subdivision, the reconstruction of political events is hotly debated among researchers.