The kingdom of Bactria had made vast advances under Euthydemus, whose son Demetrius crossed the Indian Caucasus and began the Indian conquests, which soon carried the Greeks far beyond the farthest point of Alexander. The object, it is plain, was to reach the sea and get a share in the trade of the world; and it is possible that the extension of the power of the Bactrian Greeks over Chinese Tatary as far as the Seres and Phaunians had a similar object--to protect the trade-route with China. For the Seres are the Chinese, and the Phauni, according to Pliny, lay west of the Attacori (the mythical people at the sources of the Hwangho). They occupied, therefore, the very region which, according to Chinese sources, was then held by a nomadic pastoral people, the Tibetan No-kiang. Demetrius, having succeeded his father, was displaced in Bactria by the able usurper Eucratides, sometime between 181 and 171 B.C. A thousand cities obeyed Eucratides, and both he and his rival Demetrius sought to extend the Greek settlements. Now Justin tells us that the Bactrians were so exhausted by wars that they at length fell an easy prey to the weaker Parthians; but Eucratides he describes as a valiant prince, who once with three hundred men held out during five months, though besieged by sixty thousand men of Demetrius, king of India; and then, receiving succours, subdued India. This implies that besides the kingdom of Bactria and that of Demetrius (the latter now confined to India and probably to the lands east of the Indus) there were independent states in various districts still Seleucid in 206 B.C. Justin’s statement is confirmed by the coins, which also show that Eucratides came forth as victor from a series of wars with the lesser states. Sogdiana, according to Chinese authorities, was occupied by the Scythians in the life-time of Eucratides. [Sidenote: [155-138 B.C.]] On his way back from India Eucratides was murdered by his son and co-regent, probably Heliocles [_ca._ 155 B.C.]. The date of this murder may be fixed by that of Demetrius, who must have been born not later than 224 B.C., and may be taken to have lost his kingdom not later than 159 B.C. Eucratides cannot, according to Justin’s account, have lived many years longer.