In my opinion, the most important characteristic of the ancient state is marked social stratification. The reason social stratification is so important is because it gives rise to elites with eventual hereditary status who have the state authority required to encourage, if not force, all other characteristics associated with the state. Other characteristics were important as well, but they did not have the sway of social inequality. Agriculture was a necessary characteristic, yet many agricultural societies were not states, indicating agriculture alone is not the deciding factor. Urbanism is also necessary, yet without central authority urbanism merely leads to chaos. Specialization is also a factor, often giving rise to the elite, yet it is not the only factor that causes stratification. Stratification is generally caused by one person amassing more wealth, or controlling production or trade. While specialization and the complex economy help fuel stratification, neither are necessary for the beginnings of it as even hunter-gatherer societies can have marked social stratification. Finally, state authority may be the most important characteristic in making a society a state rather than a chiefdom, but stratification is what actually causes this to occur; it is the catalyst that brings about states, making it the most important.
Stratification can be seen in all states, particularly in mortuary contexts. The more complex or elaborate the grave, the higher the status. For example, ancient Egyptians built their pharaohs enormous pyramids as tombs. The pharaoh’s tomb was filled with rich grave goods and large texts of incantations to ease his passage to the afterlife. Grave goods included jewelry made of lapis lazuli or gold, ceramics, figurines, foodstuffs, sacrificial animals (including lions) and the like. The elite attempted to bury themselves as close as possible to the pharaoh, showing his status. In fact, during periods leading up to collapse, this tradition switched to elites burying themselves regionally, indicating the pharaoh had lost some sway over the people. Ancient Mesopotamians created enormous pits for the graves of their rulers, filled with rich goods and attendants for the afterlife. The tomb of Queen Puabi contained 52 sacrificed attendants, another nearby tomb contained over 70! In the earlier era of the state, Chinese rulers were also buried with sacrificed attendants. The elite were buried with elaborate bronzes, pottery, and various artifacts. Rulers were often buried with terra cotta statues, chariots, foodstuffs, and even larger amounts of pottery and bronzes. Overall, these graves show the extreme status of rulers and other elite. It is clear that these rulers had state authority, based on the power and status that can be seen in the graves. In order to have such authority, one needs the status required. That is where social stratification comes into play, as without stratification there would be no state authority and no way for the rulers to assert their authority.