Han Chinese settled the plain in 1000 BC. Following the demise of the Eastern Han dynasty in AD 220, warlords skirmished for control from the Yellow River (Huáng Hé) basin all the way through to the southwest regions. Initially weak, the warlords along the Yangzi River finally united and defeated military groups in what is modern-day Húběi. The resultant political manoeuvrings and continued armed struggle ultimately gave rise to the Three Kingdoms Period (AD 220–60). Around the 7th century the region was intensively settled and cultivated, and by the 11th century it was producing a rice surplus, an extraordinary agricultural output that still continues today. In the late 19th century Húběi was the first area in the Chinese interior to undergo significant industrialisation.