power. There had to be a supreme ruler because, in the worship of Heaven
which was recognized by all the feudal lords, the supreme sacrifices
could only be offered by the Son of Heaven in person. There could not be
a number of sons of heaven because there were not a number of heavens.
The imperial sacrifices secured that all should be in order in the
country, and that the necessary equilibrium between Heaven and Earth
should be maintained. For in the religion of Heaven there was a close
parallelism between Heaven and Earth, and every omission of a sacrifice,
or failure to offer it in due form, brought down a reaction from Heaven.
For these religious reasons a central ruler was a necessity for the
feudal lords. They needed him also for practical reasons. In the course
of centuries the personal relationship between the various feudal lords
had ceased. Their original kinship and united struggles had long been
forgotten. When the various feudal lords proceeded to subjugate the
territories at a distance from their towns, in order to turn their city
states into genuine territorial states, they came into conflict with
each other. In the course of these struggles for power many of the small
fiefs were simply destroyed. It may fairly be said that not until the
eighth and seventh centuries B.C. did the old garrison towns became real
states. In these circumstances the struggles between the feudal states
called urgently for an arbiter, to settle simple cases, and in more
difficult cases either to try to induce other feudal lords to intervene
or to give sanction to the new situation. These were the only governing
functions of the ruler from the time of the transfer to the second
capital.

5 _Changes in the relative strength of the feudal states_

In these disturbed times China also made changes in her outer frontiers.
When we speak of frontiers in this connection, we must take little