A term coined by the German philosopher Karl Jaspers, the Axial Age refers to the period from the 8th century to the 3rd century CE when numerous influential religious and philosophical leaders and texts appeared across Eurasia, such as Zoroaster in Iran, the Hebrew Bible, Socrates and Plato in Greece, Buddha in India, and Laozi and Confucius in China. Morris holds up the Axial Age as an example of shared, common reactions to social development across societies, arguing that the Axial Age was a response to strong centralized high-tier states.

Cores are regions where social development was highest in Morris’s theory of history. For example, ancient Egypt and the city of Ur are cores.

Morris defines a high-end state as a strongly centralized state where administration is conducted by a large central bureaucracy. He argues that over the course of the first millennium BCE, states in both the East and West shifted towards high-end state structure. An example of this shift is Assyria under King Tiglath-Pileser III, who managed to create a more strongly centralized state after curbing the power of regional elites, reforming the taxation system, and growing the royal bureaucracy.

In contrast to high-end states, Morris defines low-end states as states with a more decentralized power structure, whereby administration is mostly or entirely handled by “local elites” (229). He defines Charlemagne’s Frankish empire as a low-end state, as Charlemagne did not have the resources or the political clout to create a strongly unified, centralized state out of the fractured Christian territories of Europe.