I. _The Reign of Alexander._--At the beginning of the 4th century B.C.
two types of political association confronted each other in the lands of
the Eastern Mediterranean,--the Persian monarchy with its huge
agglomeration of subject peoples, and the Greek city-state. Each had a
different principle of strength. The Persian monarchy was strong in its
size, in the mere amount of men and treasure it could dispose of under a
single hand; the Greek state was strong in its _morale_, in the energy
and discipline of its soldiery. But the smallness of the single
city-states and their unwillingness to combine prevented this
superiority in quality from telling destructively upon the bulk of the
Persian empire. The future belonged to any power that could combine the
advantages of both systems, could make a state larger than the Greek
_polis_, and animated by a spirit equal to that of the Greek soldier.
This was achieved by the kings of Macedonia. The work, begun by his
predecessors, of consolidating the kingdom internally and making its
army a fighting-machine of high power was completed by the genius of
Philip II. (359-336 B.C.), who at the same time by war and diplomacy
brought the Greek states of the Balkan peninsula generally to recognize
his single predominance. At the synod of Corinth (338) Philip was
solemnly declared the captain-general ([Greek: strategos autokrator]) of
the Hellenes against the Great King. The attack on Persia was delayed by
the assassination of Philip in 336, and it needed some fighting before
the young Alexander had made his position secure in Macedonia and
Greece. The recognition as captain-general he had obtained at another
synod in Corinth, by an imposing military demonstration in Greece
immediately upon his accession. Then came the invasion of the Persian
empire by Alexander in 334 at the head of an army composed both of
Macedonians and contingents from the allied Greek states. Before this
force the Persian monarchy went down, and when Alexander died eleven
years later (323) a Macedonian empire which covered all the territory of
the old Persian empire, and even more, was a realized fact.