For what I know, sumerians were mostly city states that were loosely ruled by a stronger city state, Uruk, for example. But what I don't know is if the stronger city states had the manpower and weapons to conquer another city. I read somewhere that the sumerians had around 500 professional soldiers in a city with 30000 people and that in cases of total war the number of conscripts could be around 3000. How accurate it that and how could try use this troops to conquer?
Although not Sumerian, Sargon of Akkard reigned during the same period and, according to inscriptions, supported 5400 men who he fed daily. Most writers I have read take this to mean a standing army of 5400 soldiers. However, in Warfare in the Ancient Near East to 1600 BC, William Hamblin argues that figure represents more the palace political and civil establishment. He did go on to say that a portion of that figure would have most likely been a standing unit of bodyguards. In that same book, it is mentioned that Sargon captured King Lugalzagesi in battle. So based on that account, we can at least say that armies of states sometimes did engage one another in the field. I was also argue that it would not be implausible that a state/city would surrender after its king was defeated in battle. The population of a city would depend on the surrounding territory for food. An invading army, once it had wiped out the opposing force, would then be free to ravage, loot, and burn crops. In order prevent such destruction, the city might submit