themselves with horsemen, and when these met, each in the
performance of their several duties, charges of masses naturally ensued.
This explains the value attaching in the old days to the possession of
horse-flesh and the rapid spread of the relatively new Dongola or
African strain over the then known world.

The primitive instinct of aboriginal man is to throw stones or other
missiles for purposes of defence (apes will throw anything they can
find, but they never use sticks); hence, as the Romans penetrated ever
farther amongst the barbarian tribes, their horsemen in first line found
ever-increasing need for protection against projectiles. But the greater
the weight of armour carried, the greater the demands upon the endurance
of the horse. Then, as the weight-carrying breed was expensive and, with
the decay of the Roman Empire, corruption and peculation spread, a limit
was soon placed on the multiplication of charging cavalry, and it became
necessary to fall back on the indigenous pony, which could only carry a
rider from place to place, not charge. Thus there was a gradual
levelling down of the mounted arms, the heavy cavalry becoming too heavy
to gallop and the light not good enough for united action. Against such
opponents, the lighter and better mounted tribesmen of Asia found their
task easy. They cut off the supplies of the marching infantry, filled up
or destroyed the wells, &c., and thus demonstrated the strategic
necessity of superior mobility.

With the decay of civilization discipline also disappeared, and, as
discipline consists essentially in the spirit of self-sacrifice for the
good of the community, its opposite, self-preservation, became the
guiding principle. This in turn led to the increase of armour carried,
and thence to the demand for heavier horses, and this demand working
through several centuries led ultimately to the breeding of the great
weight-carrying animals on whose existence that of medieval chivalry
depended. These horses, however, being very costly and practically
useless for general purposes, could only become the property of the
wealthy, who were too independent to feel the need of combination, and
preferred to live on the spoliation and taxation of the weak. This
spoliation eventually impelled the weaker men to combine, and at first
their combination took the form of the construction of fortified places,
against which mounted men were powerless. On the other hand, expense put
a li