Polyarchies (rule of the many) require more social and political skills than monarchies (rule of one) and hence arose later – from monarchies rather than directly from tribes. Carthage, some Greek city-states, and early Rome are almost the only ancient republics. All were at or near the Mediterranean coast. These republics mostly were oligarchies (rule of the few), but even democracies meant rule of the many but not all: Slaves and free noncitizens often outnumbered citizen families. The Greek states, monarchies or republics, formed a mutual fighting community, often vicious. Republics depended on a committed citizenship and faced a size trap. If they remained small, they remained vulnerable externally. If they expanded, they lacked mechanisms to include subdued people as citizens and became fragile internally. Only Carthage and Rome attempted major expansion, and only Rome succeeded, but this was the end of the republic. It may also be the peak of chattel slavery in world history: Soon three out of seven million people in Italy were slaves. By the year 1, republics looked like evolutionary dead ends. Monarchies, hereditary or not, prevailed.

A graph superimposes the growth–decline curves of major Runner Empires, from 3000 to 600 BCE. The Egyptian Old, Middle,and New Kingdoms dominate this period. Egypt’s sheltered location ensured stability, then suffocation. Mesopotamian states remained small, forming a mutual fighting community, until the brief rise of Akkad and Assyria. The Xia–Shang–Zhou empire took off only after 1500 BCE, and in a surprisingly northern location. It’s as if state formation in the west had begun on the Danube instead of Nile. Egypt came closest to the oikos model (state as the ruler’s household), with 90% of produce flown in and out of state storage. It might have been 83% in Sumerian city-states. This aspect of human self-domestication may have begun to retreat with the Hittite empire, and even Assyria. While the Hyksos surprised Egypt with chariots as early as around 1650 BCE, the Assyrians complemented chariots with cavalry only by 665 BCE. The era of Rider Empires was approaching.