XXVII THE MUSEUM AND LIBRARY AT ALEXANDRIA

that had once been followed by the ancestors of the Greeks and Phrygians and Macedonians. They raided, shattered and destroyed. And in the wake of the Gauls came a new conquering people out of Italy, the Romans, who gradually subjugated all the western half of the vast realm of Darius and Alexander. They were an able but unimaginative people, preferring law and profit to either science or art. New invaders were also coming down out of central Asia to shatter and subdue the Seleucid empire and to cut off the western world again from India. These were the Parthians, hosts of mounted bowmen, who treated the Græco-Persian empire of Persepolis and Susa in the third century B.C. in much the same fashion that the Medes and Persians had treated it in the seventh and sixth. And there were now other nomadic peoples also coming out of the northeast, peoples who were not fair and Nordic and Aryan- speaking but yellow-skinned and black-haired and with a Mongolian speech. But of these latter people we shall tell more in a subsequent chapter.