As the Greek state was founded, notions about what could be understood as broader Hellenism in that era changed dramatically. The national state aspired to play the role of a national centre, keeping alive its links with the 'unliberated brothers', the Christians of the Ottoman Empire and the Greeks of the diaspora.
This policy was attempted through the actions of state institutions, such as consular authorities and educational mechanisms, or through the creation of regulatory models for education, society and politics.

This was a two-way process, since diaspora Greeks offered the new Greek state financial support through donations and legacies. Colonial Hellenism also constituted a communication channel with other societies, such as those of Western and Central Europe.
Finally, the diaspora Greeks took political action inside the Greek state, developing a special political discourse regarding important issues concerning Hellenism, sometimes with a critical attitude towards dominant political perceptions and practices. The centres of these activities were civil communities in big ports and economic centres, such as London and especially Trieste.

During the 19th century, the Greek diaspora changed. The geographical expansion of Greek communities, their economical level, the character and social position of their members and their relationship with local populations and new state entities, gradually changed. The development of nationalistic tendencies in south-eastern Europe and the change in economic axes caused London, Manchester, Liverpool, Marseille, and Trieste and Alexandria, which were closer to Greece, to be distinguished as powerful centres of colonial Hellenism.

The Greek Orthodox communities of Central Europe and the Balkans went through a period of decline, which presaged their disappearance in the subsequent phase. After the financial degradation and hostility of the developing local capitals, they also went through administrative restrictions and were openly persecuted: typical examples were the Greek communities of Bulgaria, the Black Sea and the interior of Eastern Rumelia.
Around the Black Sea, during the second half of the 19th century, the Greeks - mostly those from Pontus - began to move en masse towards Russian provinces.
As a result of the Russo-Ottoman wars (1853-56 and 1877-78), tens of thousands of Greeks moved from Pontus in Asia Minor to Lesser Caucasus and the eastern and northern coasts. This movement balanced the negative consequences of the development of a domestic urban class, which had a negative attitude towards the privileges of old Greek commercial colonies like Odessa.

At the end of the century, a new chapter was opened for the Greeks of the diaspora, as the working class and disinherited layers of the population emigrated, hesitantly at first, to America.