9:13–21 The Roman Empire feared an attack of the Parthians from beyond the Euphrates (v. 14), the eastern border of the empire. But all such fears are dwarfed by what Revelation pictures. Outside threats experienced by the Roman Empire presage the final day of cosmic battle (16:14). The events of these verses are similar to those of 16:14, but the consequences are less severe, leaving time for repentance (vv. 18–21).