[citation needed] Serbs fleeing the Turkish advance arrived later in what was then Hungary, but most stayed in the area that is now part of Serbia.

In the 17-18th centuries, during the conflict with Protestants, many Hungarians joined the Greek Catholic Church, and so adopted the Byzantine Rite rather than the Latin, which resulted in a considerable increase in their number.

Representatives of 58 Hungarian-speaking parishes met in 1868 and set up an organization to promote the liturgical use of the Hungarian language and the establishment of a separate eparchy.

[citation needed] Finally, on 8 June 1912, Pope Pius X established the Eparchy of Hajdúdorog[6][7] for the 162 Hungarian-speaking Greek Catholic parishes.

He limited the use of Hungarian to non-liturgical functions, requiring the clergy to use Greek in the liturgy, but granted an interval of three years for the change of language to be effected.

[citation needed] The change of national frontiers after the First World War led to the reduction of the territory of the Eparchy of Hajdúdorog from the 168 parishes to which it had grown to only 90.