Let me generalize it.
People were once nomads. They went from place to place; the men hunted, while the women picked berries and tended to the children.
Then agriculture was invented. Because of this, the nomads no longer had to move from place to place. They started producing food, and the longer they stayed, the more people that formed that one place. Soon, production left over surpluses — a ton of agricultural product, way more than the new society could handle. That is when rules come in place, especially as agriculture becomes a big trade asset. Guards are made to protect the surplus, and an emperor is appointed, either by force or by ‘divinity’ (one such story could be that he prayed for rain and then rain came, and everyone praised him). From there, the society continues to grow and divide as men and women take on different roles, and different classes are created for different purposes (serfs to tend to agriculture, merchants to transport and trade it, etc.). Over time the society grows into an empire