<Table> <Tr> <Th_colspan="2"> First Arab Siege of Constantinople </Th> </Tr> <Tr> <Td_colspan="2"> Part of the Arab--Byzantine wars </Td> </Tr> <Tr> <Td_colspan="2"> Map of the environs of Constantinople in Byzantine times </Td> </Tr> <Tr> <Td_colspan="2"> <Table> <Tr> <Th> Date </Th> <Td> 674--678 </Td> </Tr> <Tr> <Th> Location </Th> <Td> Constantinople, Sea of Marmara </Td> </Tr> <Tr> <Th> Result </Th> <Td> Decisive Byzantine Empire victory </Td> </Tr> </Table> </Td> </Tr> <Tr> <Th_colspan="2"> Belligerents </Th> </Tr> <Tr> <Td> Byzantine Empire </Td> <Td> Umayyad Caliphate </Td> </Tr> <Tr> <Th_colspan="2"> Commanders and leaders </Th> </Tr> <Tr> <Td> Constantine IV </Td> <Td> Yazid I Sufyan ibn' Awf Gunada ibn Abu Umayya Fadhala ibn' Ubayd </Td> </Tr> <Tr> <Th_colspan="2"> Strength </Th> </Tr> <Tr> <Td> 22,000 Byzantine Forces </Td> <Td> <P> 40,000 Umayyad Forces </P> 700 Ships </Td> </Tr> <Tr> <Th_colspan="2"> Casualties and losses </Th> </Tr> <Tr> <Td> 3,000 Killed </Td> <Td> 13,000 Killed or Drowned </Td> </Tr> </Table> <Tr> <Th_colspan="2"> First Arab Siege of Constantinople </Th> </Tr>

What secret weapon helped to hold off invaders to constantinople