After the re-occupation of Western Ukraine by the Red Army in 1944, a campaign against the Ukrainian Catholic Church began quickly. The Soviet authorities saw the Church as a threat to Soviet power. Metropolitan Andriy Sheptytsky died in November 1944 and Josyf Slipyj was installed as his successor. Under his leadership the Church refused to bow to Soviet pressure to take part in Soviet propaganda efforts and to denounce the Ukrainian nationalist movement. As a result attacks on the Church began in earnest in early 1945. Slipyj and several other bishops were arrested in April 1945 and in June 1946 sentenced to lengthy terms in the Gulag.

In May 1945 a “Sponsoring Group for the Re-Union of the Greek Catholic Church with the Russian Orthodox Church” was established, and proclaimed itself the only legitimate leadership of the Ukrainian Catholic Church. An intense campaign began to convince the clergy of the Church to agree to “re-unification.” Those who would not agree were subject to pressure and threats by the secret police; many were arrested.

After the resistance of the clergy was broken a Sobor was held on March 8-10 1946 in Lviv. In order for the liquidation of the Ukrainian Catholic Church to appear canonical, a vote was held on a resolution abolishing the Union of Berestia and ‘returning’ the Ukrainian Catholic Church to the patriarchy of Moscow. The Soviet electoral tradition was extended to the Church as well – the delegates voted unanimously with a show of hands for ‘re-unification.’

This farce was followed by an intense wave of repression against clergy and laypersons that refused to accept the liquidation of their Church. The Church went into the underground; secret liturgies were held, priests were ordained in secret, and many people in Western Ukraine continued to practice their faith in the underground. The Soviet authorities legalized the Church in December 1989.