After the battle of Mantinea, Athens stood as the most powerful state with two possible future enemy powers, both kingdoms, Caria (both a land and sea power) and Macedonia (a land power). Of the two, Athens considered Caria to pose a threat, but it was Macedonia that developed into the force to occupy the entire known world. When Philippos II came to power in 359 B.C. at the age of 23, he secured a peace treaty with Athens and faced the neighbouring danger that was coming from the Paeonians and the Illyrians. After defeating them his next task was to get hold of the mines in Paggaio, which would provide him with enough gold to compensate for the lack of trade that was keeping the region poor. The gold now gave him the power to open up new roads and create, for the first time in history, a professional army, which would form the Macedonian Phalanx-a lightly armed and flexible unit resembling the usual battle line of Greek spearmen. His next step was to secure his kingdom from the Greek city-states and especially Athens and Thebes. In 339 B.C. he defeated their joined forces in Chaeronia and he united the Greek city-states in an alliance under the hegemony of Macedonia with the definite goal of an eastward expedition. Little is known about Philippos and most of the knowledge we have comes from his great opponent the Athenian orator Demosthenes. At the age of 30, Demosthenes delivered one of the most effective speeches his First Philippic, on the advance of Philippos to Propontis, urging the Athenians to unite against the enemy and overcome their apathy as citizens. His love for Thucydides had cultivated in him the plain but daring phraseology he used in order to draw the contrast between Philippos' energy and decisiveness and the Athenians' indifference. He accused the Athenians for "creating" Philippos and, commenting on a rumor that wanted Philippos dead, he said: "Is Philippos dead? What does it matter to you? For if this Philippos dies, you will soon raise up a second Philippos by your apathy". In order to face him and diminish his power, he proposed that Athens should keep part of the navy in northern Aegean, men should join the military and the wealthy should contribute to the expenses.

Demosthenes was applauded but he lived in Eubulous' and not in Pericles' times. His effort to invoke the imperialistic spirit of Athens was unsuccessful although his political estimates, thirteen years before the battle of Chaeronia, were correct. Throughout his three Philippics he made each man -whether leader or common citizen- responsible for the future of their city-state. Demosthenes, rooted to the Periclean past, failed to see what Isocrates had seen; the inevitable expansion of a united Greece. The battle of Chaeronia marked the end of the city-state and the beginning of the Macedonian hegemony. Philippos' dreams to march against the Persian Empire were fulfilled by his son, Alexander. Under him, the tight co-operation of the infantry and the cavalry as well as the Macedonian Phalanx would become the new conquering force. A well-organized and trained army, although small in number, extended the borders of the kingdom to India, winning the decisive battles of the Granicus River (334), of Issus (333) and of Gaugamela (331). The permanent character of his endeavor can be seen in his decision to bring along scientists to collect information and study the region. He used local governors, along with his own officers, to govern the vast area he was occupying. By founding 70 cities, by encouraging interracial marriages and by including some of the Asian customs, he tried to fuse the diverse civilizations. When he died at the age of 33 (in June 323 B.C.) he left a world of cosmopolitan attitude with emphasis on the individual character which substituted the idealism of the classical era.