The armies of the earlier period consisted mainly of the nobles in their
war chariots; each chariot surrounded by the retinue of the nobleman.
Now came large troops of commoners as infantry as well, drawn from the
peasant population. To these, cavalry were first added in the fifth
century B.C., by the northern state of Chao (in the present Shansi),
following the example of its Turkish and Mongol neighbours. The general
theory among ethnologists is that the horse was first harnessed to a
chariot, and that riding came much later; but it is my opinion that
riders were known earlier, but could not be efficiently employed in war
because the practice had not begun of fighting in disciplined troops of
horsemen, and the art had not been learnt of shooting accurately with
the bow from the back of a galloping horse, especially shooting to the
rear. In any case, its cavalry gave the feudal state of Chao a military
advantage for a short time. Soon the other northern states copied it one
after another--especially Ch'in, in north-west China. The introduction
of cavalry brought a change in clothing all over China, for the former
long skirt-like garb could not be worn on horseback. Trousers and the
riding-cap were introduced from the north.

The new technique of war made it important for every state to possess as
many soldiers as possible, and where it could to reduce the enemy's
numbers. One result of this was that wars became much more sanguinary;
another was that men in other countries were induced to immigrate and
settle as peasants, so that the taxes they paid should provide the means
for further recruitment of soldiers. In the state of Ch'in, especially,
the practice soon started of using the whole of the peasantry
simultaneously as a rough soldiery. Hence that state was particularly
anxious to attract peasants in large numbers.

2 _Economic changes_

In the course of the wars much land of former noblemen had become free.
Often the former serfs had then silently become landowners. Others had
started to cultivate empty land in the area inhabited by the indigenous
population and regarded this land, which they themselves had made
fertile, as their private family property. There was, in spite of the
growth of the population, still much cultivable land available.
Victorious feudal lords induced farmers to come to their territory and
to cultivate the wasteland. This is a period of great migrations,
internal and external. It seems t