Part 11/15:
Historically, every great civilization experiences a cycle of ascendancy, decadence, and decline. Dominant empires—be they the Romans, Chinese dynasties, or Islamic caliphates—are often challenged or destabilized by the steppe’s barbarians, who are products of its environment: rugged, demanding, and inherently martial.
The Mongols, for instance, unified the steppe in the 13th century and created the largest land empire in history. Their conquests disrupted the economic and cultural centers of Eurasia, causing a decline in the wealth and stability of regions like Persia and China, which soon entered periods of stagnation and conservative retrenchment.