<Tr> <Th_colspan="9"> House of Sasan </Th> </Tr> <Tr> <Td> </Td> <Td> Shahanshah, Aparviz </Td> <Td> Khosrau II </Td> <Td>--</Td> <Td> 570 </Td> <Td> Son of Hormizd IV </Td> <Td> January 591--25 February 628 </Td> <Td> February 28, 628 </Td> <Td> Executed by Mihr Hormozd under the orders of Kavadh II </Td> </Tr> <Tr> <Th_colspan="9"> House of Ispahbudhan </Th> </Tr> <Tr> <Td> </Td> <Td> Shahanshah </Td> <Td> Vistahm </Td> <Td>--</Td> <Td>? </Td> <Td> Son of Shapur from the House of Ispahbudhan . He was the uncle of Khosrau II and husband of Gorduya, sister of Bahram VI </Td> <Td> 591--596 or 600 </Td> <Td> 596 or 600 </Td> <Td> Killed by his wife Gorduya or by his general Pariowk </Td> </Tr>

Who was the ruler of the persian empire