<Tr> <Td_colspan="8"> Eastern Han </Td> </Tr> <Tr> <Td_colspan="8"> Three Kingdoms 220--280 </Td> </Tr> <Tr> <Td_colspan="8"> Wei, Shu and Wu </Td> </Tr> <Tr> <Td_colspan="8"> Jin dynasty 265--420 </Td> </Tr>

What led to the downfall of the tang dynasty