The situation in the north, in the state of Wei (220-265) was anything but rosy.  Wei ruled what at that time were the most important and richest regions of China, the plain of Shensi in the west and the great plain east of Loyang, the two most thickly populated areas of China.  But the events at the end of the Han period had inflicted great economic injury on the country.  The southern and south-western parts of the Han empire had been lost, and though parts of Central Asia still gave allegiance to Wei, these, as in the past, were economically more of a burden than an asset, because they called for incessant expenditure.  At least the trade caravans were able to travel undisturbed from and to China through Turkestan.  Moreover, the Wei kingdom, although much smaller than the empire of the Han, maintained a completely staffed court at great expense, because the rulers, claiming to rule the whole of China, felt bound to display more magnificence than the rulers of the southern dynasties.  They had also to reward the nineteen tribes of the Hsiung-nu in the north for their military aid, not only with cessions of land but with payments of money.  Finally, they would not disarm but maintained great armies for the continual fighting against the southern states.  The Wei dynasty did not succeed, however, in closely subordinating the various army commanders to the central government.  Thus the commanders, in collusion with groups of the gentry, were able to enrich themselves and to secure regional power.  The inadequate strength of the central government of Wei was further undermined by the rivalries among the dominant gentry.  The imperial family (Ts’ao Pei, who reigned from 220 to 226, had taken as emperor the name of Wen Ti) was descended from one of the groups of great landowners that had formed in the later Han period.  The nucleus of that group was a family named Ts’ui, of which there is mention from the Han period onward and which maintained its power down to the tenth century; but it remained in the background and at first held entirely aloof from direct intervention in high policy.  Another family belonging to this group was the Hsia-hou family which was closely united to the family of Wen Ti by adoption; and very soon there was also the Ss[)u]-ma family.  Quite naturally Wen Ti, as soon as he came into power, made provision for the members of these powerful families, for only thanks to their support had he been able to ascend the throne and to maintain his hold on the throne.  Thus we find many members of the Hsia-hou and Ss[)u]-ma families in government positions.  The Ss[)u]-ma family especially showed great activity, and at the end of Wen Ti’s reign their power had so grown that a certain Ss[)u]-ma I was in control of the government, while the new emperor Ming Ti (227-233) was completely powerless.  This virtually sealed the fate of the Wei dynasty, so far as the dynastic family was concerned.  The next emperor was installed and deposed by the Ss[)u]-ma family; dissensions arose