of depression
which was at the same time a period of reconstruction. They were
beginning slowly to form together with Mongol elements a new unit, the
Juan-juan, but at this time were still politically inactive. The
nineteen tribes within north China held more and more closely together
as militarily organized nomads, but did not yet represent a military
power and remained loyal to the Wei. The only important element of
trouble seems to have been furnished by the Hsien-pi tribes, who had
joined with Wu-huan tribes and apparently also with vestiges of the
Hsiung-nu in eastern Mongolia, and who made numerous raids over the
frontier into the Wei empire. The state of Yen, in southern Manchuria,
had already been destroyed by Wei in 238 thanks to Wei's good relations
with Japan. Loose diplomatic relations were maintained with Japan in the
period that followed; in that period many elements of Chinese
civilization found their way into Japan and there, together with
settlers from many parts of China, helped to transform the culture of
ancient Japan.

(B) The Western Chin dynasty (A.D. 265-317)

1 _Internal situation in the Chin empire_

The change of dynasty in the state of Wei did not bring any turn in
China's internal history. Ss[)u]-ma Yen, who as emperor was called Wu Ti
(265-289), had come to the throne with the aid of his clique and his
extraordinarily large and widely ramified family. To these he had to
give offices as reward. There began at court once more the same
spectacle as in the past, except that princes of the new imperial family
now played a greater part than under the Wei dynasty, whose ruling house
had consisted of a small family. It was now customary, in spite of the
abolition of the feudal system, for the imperial princes to receive
large regions to administer, the fiscal revenues of which represented
their income. The princes were not, however, to exercise full authority
in the style of the former feudal lords: their courts were full of
imperial control officials. In the event of war it was their duty to
come forward, like other governors, with an army in support of the
central government. The various Chin princes succeeded, however, in
making other governors, beyond the frontiers of their regions, dependent
on them. Also, they collected armies of their own independently of the
central government and used those armies to pursue personal policies.
The members of the families allied with the ruling house,