During the centuries after the fall of the Han dynasty, dozens of states rose and fell in geographic China, which was not only politically divided but also home to multiple separately named population groups, some of which were speakers of languages unrelated to Chinese. Yet, a single written language was used throughout the region, broadly common institutions were everywhere in place, and there was a widely shared collective historical memory. This memory included an assumed single line of legitimate sovereigns stretching back to the Sage Kings of legendary antiquity. Differently named population groups could adopt that written language, institutions, and historical memory, and their rulers could potentially even join that line of legitimate sovereigns. It was therefore relatively easy for the Sui and Tang dynasties, having militarily unified the geographic space of the old Han empire, to successfully depict themselves as heirs to a unitary China rooted in ancient memory.
