THE ARYAN MIGRATIONS 37 of the Persian nobility, and aided by a conspiracy among the Medes, overthrew the ruling Median dynasty, and made himself monarch of all Media. A monarchy so won could only be maintained by continuous conquests ; and while Nabonidus of Babylon was dreaming of inscriptions, Cyrus the Persian turned his arms against the monarch of Lydia, whom he conquered, and whose territory he annexed. Croesus had realised his danger, and attempted to gather allies to check the Median advance ; but he was already overthrown before the allies were ready to come to his help. Then Cyrus turned on Babylon, and captured the great city by a remarkable Fall of engineering feat. Babylon was protected by the Babylon. Euphrates ; but Cyrus, by a system of canals, diverted the course of the river, and so was able to enter the city. Its capture, which the Bible narrative attributes by an error to Darius, one of the successors of Cyrus, made him master of the whole Babylonian Empire. Cyrus himself was slain while leading a great expedition against the barbarian tribes on the east of the Caspian Sea, who were included in the general name of Scythian, applied by the Greeks to all the nomadic hordes who dwelt beyond civilised regions; some of which were probably Slavonic Aryans, while others were of those Mongolian races which later times have named Tartars or Turks. Cyrus was succeeded by his son Cambyses. Cambyses left the Scythians alone, having found a pretext for invading the great southern empire of Egypt. Here for the CambvseB last forty years there had ruled a usurper whom conquers the Greeks called Amasis, to whom Croesus had E £ ypt * appealed in vain for aid against Cyrus. His successor Psammetichus had been on the throne only a few months, when the invader arrived and crushed his armies in one great battle which laid all Egypt at his mercy. Thus the Persian Cambyses was lord of the whole civilised world in Asia and Africa, except the comparatively remote state of Carthage. The reign of Cambyses was brief. On his death the Imperial throne was captured by an impostor professing to be Smerdis,
