The period of Chinese history between the fall of the Han dynasty in 220 AD and the founding of the Sui dynasty in 589, during which six dynasties had capitals in the south at Nanjing, while North China was ruled by barbarian dynasties. They were: the Wu (222-280), the Eastern Chin (317-420), the Liu-Sung (420-479), the Southern Ch'i (479-502), the Southern Liang (502-557), and the Southern Ch'en (557-589). In the course of the Six Dynasties period, Buddhism came to be firmly established. Six Dynasties tombs have contributed notably to the study of ceramics and early pictorial art. Great advances were made in medicine, astronomy, botany, and chemistry - and major changes took place in the arts and architecture. Wheelbarrows and kites were invented, coal was first used as a fuel, and it was also during the Six Dynasties that the great aristocratic families began to arise in Chinese society.