descendants form the principal components of the Tai in Thailand, the
Shan in Burma and the Lao in Laos. Their immigration into the areas of
the Shan States of Burma and into Thailand took place only in quite
recent historical periods, probably not much earlier than A.D. 1000.

Finally there arose from the mixture of the Yao with the Tai culture, at
a rather later time, the Yüeh culture, another early Austronesian
culture, which then spread over wide regions of Indonesia, and of which
the axe of rectangular section, mentioned above, became typical.

Thus, to sum up, we may say that, quite roughly, in the middle of the
third millennium we meet in the _north_ and west of present-day China
with a number of herdsmen cultures. In the _south_ there were a number
of agrarian cultures, of which the Tai was the most powerful, becoming
of most importance to the later China. We must assume that these
cultures were as yet undifferentiated in their social composition, that
is to say that as yet there was no distinct social stratification, but
at most beginnings of class-formation, especially among the nomad
herdsmen.


6 _The Yang-shao culture_

The various cultures here described gradually penetrated one another,
especially at points where they met. Such a process does not yield a
simple total of the cultural elements involved; any new combination
produces entirely different conditions with corresponding new results
which, in turn, represent the characteristics of the culture that
supervenes. We can no longer follow this process of penetration in
detail; it need not by any means have been always warlike. Conquest of