After The Encyclical
From 1945-1958, six Ukrainian bishops were murdered, sentenced to death or died in the Gulag. In 1949, Pope Pius made Slipyi cardinal in pectore, that is to his on safety, it remained a secret. In 1957, he congratulated him to the 40th. anniversary of his priesthood. But Slipyi remained jailed until 1963. The Ruthenian Church continued to suffer. The Soviet authorities soon initiated persecution of the Ruthenian Church in the newly acquired region. In 1946 the Uzhorod seminary was closed. In 1949 the Ruthenian Catholic Church was integrated into the Russian Orthodox Church. Rusyns on the other side of the Czechoslovak border were also forced to become Orthodox, while those in the Polish Lemko region were deported en masse in 1947 either to the Soviet Union or other parts of Poland.
Read more about this topic: Orientales Omnes Ecclesiae