[1] Grechishkin was born near Charkov (in modern Ukraine) into the family of an Orthodox priest.
[1] In 1920, he emigrated to Czechoslovakia due to Russian Communist persecution against Orthodoxy.
[1] Grechishkin participated in a mission against the Carpathian Greek Catholics, during which he interested about Uniatism.
In 1930, believing in the Roman Catholic Church, he converted from Orthodoxy.
In Paris when Cardinal Eugène Tisserant appointed him rector and was elevated to the rank of archpriest.