Kingship was a _bala_, a “reversion,” or “return to origin.” In other words, the kingly office had a limited tenure; at the end of the emergency authority reverted to the assembly. But, in practice, the threat of an emergency was never absent once the cities flourished and increased in number. Contiguous fields, questions of drainage and irrigation, the safeguarding of supplies by procuring safety of transit—all these might become matters of dispute between neighbouring cities. We can follow through five or six generations a futile and destructive war between Umma and Lagash with a few fields of arable land as the stakes. Under such conditions the kingship seems to have become permanent in certain cities. Elsewhere the concentrated authority called for by the dangers to which the community was frequently exposed was conferred upon leaders who held important permanent offices. Some of these were exalted enough to enable their holders, when emergencies arose, to exercise power similar to that of the _lugal_. The _sangu_ or _nubanda_ in the temple of the city god was the administrative leader of the most important temple community in the city. For him to become the political leader of the city was perfectly feasible, but in such a case the official who had usurped the prerogatives of a ruler assumed, instead of the secular title _lugal_, a title emphasizing his dependence on the city god and proclaiming, by implication, the god’s agreement with his rule. This title was _ensi_, best translated as “governor” (viz. of the god). Whether _lugal_ or _ensi_, the city ruler in Mesopotamia did not derive his position from any innate superiority or right of birth. He acted either on behalf of the assembly, or as steward of the real sovereign, the city god. In theology, personal rule was sanctioned by a doctrine of divine election which remained the foundation of kingship down to the end of the Assyrian empire. Divine approval could be withdrawn at any time, and the formation of a dynasty, the succession of the son to the throne of the father, although known already in Early Dynastic times, had no basis in the theory of kingship but was interpreted in each case as a sign of favour bestowed by the gods. These limiting conceptions of the monarchy reflect the preponderant influence of the city in Mesopotamian thought. Monarchy remained a problematical institution and failed, therefore, to become an instrument of unity as it did in Egypt. It carried in some degree the taint of usurpation, especially in early times.