XXVII THE MUSEUM AND LIBRARY AT ALEXANDRIA Before the time of Alexander Greeks had already been spreading as merchants, artists, officials, mercenary soldiers, over most of the Persian dominions. In the dynastic disputes that followed the death of Xerxes, a band of ten thousand Greek mercenaries played a part under the leadership of Xenophon. Their return to Asiatic Greece from Babylon is described in his Retreat of the Ten Thousand, one of the first war stories that was ever written by a general in command. But the conquests of Alexander and the division of his brief empire among his subordinate