<Tr> <Td_colspan="3"> Roman Empire </Td> </Tr> <Tr> <Td_colspan="3"> Senatus Populusque Romanus Imperium Romanum </Td> </Tr> <Tr> <Td_colspan="3"> Western division of the Roman Empire (285--480) </Td> </Tr> <Tr> <Td_colspan="3"> <Table> <Tr> <Td> </Td> <Td> 285--476 / 480 </Td> <Td> </Td> </Tr> </Table> </Td> </Tr>

When did the roman empire replace the roman republic