<Tr> <Td_colspan="8"> Xia dynasty c. 2070--c. 1600 BC </Td> </Tr> <Tr> <Td_colspan="8"> Shang dynasty c. 1600--c. 1046 BC </Td> </Tr> <Tr> <Td_colspan="8"> Zhou dynasty c. 1046--256 BC </Td> </Tr> <Tr> <Td_colspan="8"> Western Zhou </Td> </Tr>

What did tang leaders do to help rule this large empire