Question: Who had the most power in sumerian society?
Disambiguated questions and answers: question: Who had the most power in the earliest ancient sumerian society?
Who had the most power in later ancient sumerian society?
answer: a priestly governor (ensi) or by a king (lugal)
king (lugal)
theocratic priests and religious officials
priestly governor (ensi)
Kings
Natural Questions answer: kings (from the Wikipedia article "Sumerian religion")