During the Western Han period, relying on the rich resources of the Mount Dakui (), Mount Yi () and Mount Song region, Gongyi to the West of Zhengzhou and Xingyang both became important national iron smelting centers. Xingyang established an Iron Bureau and many remnants of large scale Han Dynasty iron smelting and pig iron production have been unearthed in the area, demonstrating that at that time the Han people had already reached the highest standards of metal casting. The Eastern Han Period saw successive revolts and land seizures beginning with the Yellow Turban Rebellion in 184 CE. Cao Cao occupied the Central China Plain and in 200 CE defeated Yuan Shao at the Battle of Guandu, northeast of present-day Zhongmu County. After Emperor Hui of Jin ascended the throne in 290 CE, uprisings such as the War of the Eight Princes and the Disaster of Yongjia occurred frequently and continued until the time of the Later Zhao during the Sixteen Kingdoms Period. Throughout this time, Zhengzhou witnessed unrest with a slump in agriculture and frequent crop failures. During the Northern Wei Dynasty Indian Buddhist disciple Bodhidharma arrived and remained at the Shaolin Temple on Mount Song where stared at a wall for nine years and passed on the teachings of Buddha to the Chinese Chán disciple Dazu Huike.