Bulgarian Greek Catholic Church
[2] Under Knyaz Boris (853–889) the Bulgarians accepted Christianity in its Byzantine form, with the liturgy celebrated in Church Slavonic.
For a variety of reasons, Boris became interested in converting to Christianity and undertook to do that at the hands of Western clergymen to be supplied by Louis the German in 863.
Wanting to bear the title of Emperor and to restore the prestige, wealth and size of the First Bulgarian Empire, Kaloyan responded in 1202.
[4] The pope was not willing to make concessions on that scale, and when his envoy, Cardinal Leo, arrived in Bulgaria, he anointed the Archbishop Vasilij of Tărnovo as Primate of Bulgarians.
Meanwhile, in an attempt to foster an alliance with Kaloyan, the Byzantine Emperor Alexios III Angelos recognized his imperial title and promised him patriarchal recognition.
They were connected to the nationalist emancipation from the Greek-dominated Patriarchate of Constantinople and its pro-Greek influence over the Slavic population living in the Thracian and Macedonian lands.
The movement for union with Rome initially won some 60,000 adherents, but, as a result of the Sultan's establishment in 1870 of the Bulgarian Exarchate, at least three quarters of these returned to Orthodoxy by the end of the 19th century.
The clergy's numerous shifts from the Orthodox to the Catholic Church and vice versa should not be viewed only as personal whims.
The Ottoman Empire's attitude was ambivalent – sometimes supporting, sometimes opposing the Uniat movement, depending on how it had to balance its own interests in the game with the Great Powers.
The leading figure of the Uniat movement was the Bulgarian merchant Dragan Tsankov, who had the support of Catholic France.
In return, they demanded that no changes should be introduced to their Eastern rites of worship and that they would be the ones to choose their bishops and lower clergy, with the approval of the Pope.
The letter stated that the teachers at the church schools are to be chosen by the domestic clergy and the education is to be pursued in the Bulgarian language and its "national alphabet".
Two months after, Izvorov arrived in Kukush as an Orthodox bishop, he was called back to Constantinople by the Patriarchate and the Russian diplomatic services.
Historical sources show that the Ottoman government banned Izvorov from entering Kukush for several years.
In the same year Izvorov was promoted to be the Administering Bishop of all Uniat Bulgarians, directly subordinated to the Apostolic Delegate in Constantinople.
After the High Porte cancelled his accreditation as Bishop on the demand of the French Consul in Salonica in 1894, Mladenov also turned to the Bulgarian Exarchate.
By the end of the 19th century, the Bulgarian Greek Catholic Church in Macedonia was based in Kukush with Epiphany Shanov as Bishop after Mladenov's excommunication in 1895.
In 1893, the Internal Macedonian-Adrianople Revolutionary Organization emerged as the main Bulgarian factor in the Macedonian and Thracian lands.
The immediate effect of the partition of the Ottoman Empire during the Balkan Wars was the anti-Bulgarian campaign in areas under Serbian and Greek rule.
[8] The Ottomans managed to keep the Adrianople region, where the whole Thracian Bulgarian population was put to total ethnic cleansing by the Young Turks' army.
