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Kyrylo Korolevsky (Jean François Joseph Charon) was a priest, a Frenchman by birth, whose life was closely connected with the Ukrainian Greek Catholic Church. He was an extremely talented, educated, inquisitive man, a true researcher-scientist, who was well known and appreciated in the highest circles of the Roman Curia.
Brought up in Catholic traditions, at a certain stage of his life he became interested in Eastern theology and decided to become a priest of the Eastern rite. He called himself Cyril of Korolev and later became an astonishing expert on the East. Cyril Korolevsky opposed everything that had a hint of Latinisation of the rite.
The work "Uniatism" is a vivid testimony to Korolevsky's irreconcilable position on "hybridisms" in the Eastern rite.