I want to know the answer to the following question:
What did Eannatum use to keep the people of the time in line?
All the background I'm provided with is that "Although short-lived, one of the first empires known to history was that of Eannatum of Lagash, who annexed practically all of Sumer, including Kish, Uruk, Ur, and Larsa, and reduced to tribute the city-state of Umma, arch-rival of Lagash.". Is that enough to answer the question?
Answer: no