s, and especially from
the Persians, who, according to Xenophon, held this arm in great
consideration. After the battle of Platea, it was agreed by assembled
Greece that each power should furnish one horseman to every ten
foot-soldiers. In Sparta the poorest were selected for this arm, and the
cavalry marched to combat without any previous training. At Athens the
cavalry service was more popular, and they formed a well-organized corps
of twelve hundred horsemen. At Thebes also this arm had consideration in
the time of Epaminondas. But the cavalry of Thessaly was the most
renowned, and both Philip and Alexander drew their mounted troops from
that country.

The Romans had made but little progress in this arm when they
encountered the Thessalians, who fought in the army of Pyrrhus. They
then increased their cavalry, but it was not numerous till after their
wars with the Carthaginians. Scipio organized and disciplined the Roman
cavalry like that of the Numidians. This arm was supplied from the ranks
of the richest citizens, and afterwards formed an order intermediary
between the Senate and the people, under the name of _knights_.

At a later period, the cavalry of the Gauls was particularly good. The
Franks were without cavalry when they made their first irruption into
Gaul. Under the reign of Childeric I. we see for the first time the
"cavaliers francs" figure as a part of the national forces. At the
battle of Tours the cavalry and infantry were in the proportion of one
to five, and under Pepin and Charlemagne their numbers were nearly
equal. Under Charles the Bald armies were composed entirely of cavalry,
and during the middle ages the knights disdained the foot service, and
fought only on horseback.

After the introduction of artillery, cavalry was still employed, though
to little advantage. Gustavus Adolphus was the first to perceive the
real importance of this arm in modern warfare, and he used it with great
success. But it was left for Seidlitz to perfect it under the direction
of Frederick the Great.

Marshal Saxe very justly remarked, that cavalry is the "_arme du
moment,_" for in almost every battle there are moments when a decisive
charge of cavalry will gain the victory, but if not made at the instant
it may be too late. The efficiency of cavalry depends upon the moral
impression which it makes on the enemy, and is greater in proportion to
the size of the mass, and the rapidity of its motion. This last qualit