November 1948. As the cardinal lay dying, he had asked that Wyszyński's name be forwarded to Rome as a potential replacement. Post-war resistance to Communism World War II ended in 1945; however, beginning in the eastern portion of present-day Poland, and later in the west, hostilities continued for several years between a large segment of Poles and the Stalinist government. The Catholic Church hoped for the return of the Polish government-in-exile from London and the removal of Stalin's puppet regime; it actively supported the anti-Communists. One of the prime issues was the confiscation of church property by the Communist government. In 1950, Wyszyński decided to enter into a secret agreement with the Communist authorities, which was signed on 14 April 1950 by the Polish episcopate and the government. The agreement settled the political disputes of the church versus the government in Poland. It allowed the church to hold onto "reasonable" property, separated the church from politics, and even allowed authorities to select a bishop from a list of three candidates. Beginning in 1953, another wave of persecution swept Poland. When the bishops continued their support for anti-Communist resistance, the government began holding mass trials and imprisoning priests, including Wyszyński, who had just been made cardinal. On 25 September 1953 he was imprisoned at Rywałd, and later placed under house arrest in near Lidzbark Warmiński, in Prudnik near Opole and in the Komańcza monastery in the Bieszczady Mountains. While imprisoned, he observed the brutal torture and mistreatment of detainees, some of it highly perverse in nature. He was released on 26 October 1956 following Polish October. Cardinal and Primate of Poland On 12 January 1953, Wyszyński was elevated to the rank of cardinal by Pope Pius XII, but it was not until 18 May 1957 that he was designated Cardinal-Priest of Santa Maria in Trastevere. He never stopped his religious and social work. Its crowning achievement was the celebration of Poland's Millennium of Christianity in 1966 – the thousandth anniversary of the baptism of Poland's first historical ruler, Mieszko I. During the celebration, the Communist authorities refused to allow Pope Paul VI to visit Poland and they also prevented Cardinal Wyszyński from attending celebrations abroad. Wyszyński triumphed in 1978, when Karol Wojtyła of Kraków was elected Pope John Paul II, followed by a spectacular papal visit to Poland in 1979. Wyszyński did not turn a blind eye towards the civil unrest