The ED was divided into the sub-periods ED I, II, and III. This was primarily based on complete changes over time in the plan of the Abu Temple of Tell Asmar, which had been rebuilt multiple times on exactly the same spot. During the 20th century, many archaeologists also tried to impose the scheme of ED I–III upon archaeological remains excavated elsewhere in both Iraq and Syria, dated to 3000–2000 BC. However, evidence from sites elsewhere in Iraq has shown that the ED I–III periodization, as reconstructed for the Diyala river valley region, could not be directly applied to other regions.