In the changes of government which preceded the establishment of Byzantium as the capital of the Roman Empire by Constantine, the Greeks contributed to effect a mighty revolution of the whole frame of social life by the organisation which they gave to the Church from the moment they began to embrace the Christian religion.  It awakened many of the national characteristics which had slept for ages, and gave new vigour to the communal and municipal institutions, and even extended to political society.  Christian communities of Greeks were gradually melted into one nation, having a common legislation and a common civil administration as well as a common religion, and it was this which determined Constantine to unite Church and State in strict alliance.

From the time of Constantine the two great principles of law and religion began to exert a favourable influence on Greek society, and even limited the wild despotism of the emperors.  The power of the clergy, however, originally resting on a more popular and more pure basis than that of the law, became at last so great that it suffered the inevitable corruption of all irresponsible authority entrusted to humanity.

Then came the immigration and ravages of the Goths to the south of the Danube, and that unfortunate period marked the commencement of the rapid decrease of the Greek race, and the decline of Greek civilisation throughout the empire.  Under Justinian (527-565), the Hellenic race and institutions in Greece itself received the severest blow.  Although he gave to the world his great system of civil law, his internal administration was remarkable for religious intolerance and financial rapacity.  He restricted the powers and diminished the revenues of the Greek municipalities, closed the schools of rhetoric and philosophy at Athens, and seized the endowments of the Academy of Plato, which had maintained an uninterrupted succession of teachers for 900 years.  But it was not till the reign of Heraclius that the ancient existence of the Hellenic race terminated.

II.—­The Byzantine and Greek Empires

The history of the Byzantine Empire divides itself into three periods strongly marked by distinct characteristics.  The first commences with the reign of Leo III., the Isaurian, in 716, and terminates with that of Michael III., in 867.  It comprises the whole history of the predominance of iconoclasm in the established church, of the reaction which reinstated the Orthodox in power, and restored the worship of pictures and images.

It opens with the effort by which Leo and the people of the empire saved the Roman law and the Christian religion from the conquering Saracen.  It embraces the long and violent struggle between the government and the people, the emperors seeking to increase the central power by annihilating every local franchise, and to constitute themselves the fountains of ecclesiastical as completely as of civil legislation.