You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Sumer

Context:
Though women were protected by late Sumerian law and were able to achieve a higher status in Sumer than in other contemporary civilizations, the culture was male-dominated. The Code of Ur-Nammu, the oldest such codification yet discovered, dating to the Ur-III "Sumerian Renaissance", reveals a glimpse at societal structure in late Sumerian law. Beneath the lu-gal ("great man" or king), all members of society belonged to one of two basic strata: The "lu" or free person, and the slave (male, arad; female geme). The son of a lu was called a dumu-nita until he married. A woman (munus) went from being a daughter (dumu-mi), to a wife (dam), then if she outlived her husband, a widow (numasu) and she could then remarry.

Question:
Who was at the top of the power pyramid in Sumerian society?

the lu-gal