Andrzej or Andrew Bobola was a Polish national hero. In 1657, he was brutally slain by Russian occupiers, who even kept his deceased body. In 1923, Vladimir Lenin permitted the transfer of the relicts of Andrzej Bobola to the Vatican with the stipulation that they never be forwarded to Poland, since Bobola continued to stimulate anti-Russian sentiments in Poland. April 1938 Pope Pius XI canonized Bobola and sent his relics to Poland where, on June 17, 1938, he received a tumultuous and emotional welcome in Warsaw. Polish President Moscicki led the ceremonies with a flaming nationalist speech. In a grandiose gesture, he solemnly took off his own Cross of Merit Polonia Restituta, and placed it on the remains of Bobola. The Polish Communist Party was forced to disband on Bobola day June 17, 1938. Catholic theologians like J. Pastuszek openly blamed the Jews for the existence and spread of Communism  In the following weeks, anti-Russian and anti-Orthodox emotions climaxed in Poland. Some 138 Orthodox Churches were burned or destroyed. Oriental Catholic Orthodox Churches, who, because of previous persecution under the Tsars, were equally opposed to the Russian Orthodox Church, found their churches and institutions vandalized by Polish authorities as well. A few years later, the Polish Church, now under Stalinist persecution, celebrates the anniversary of the martyrdom of Bobola, which is the reason for the encyclical of Pope Pius XII.
The encyclical 
Pope Pius describes the suffering of this Polish hero saints in concrete words. But, he continues, in our days, the Catholic religion has been exposed to grave danger. The haters of God and enemies of Christian teaching attack Jesus Christ and his Church The Pope asks for endurance and bravery. The people and clergy must overcome many obstacles, and even sacrifices in time and money, but they must never give in.
Pius comforts his Polish brothers saying that everywhere, there is always a bit of martyrdom in Christian day to day life, if one strives for perfection. Bobola is a model saint because he kept his faith intact and defended it with all means. Polish people should "look to the reward God promises to all who with perfect fidelity, unflagging readiness, and burning love live, labor, and strive to defend and spread throughout the world His Kingdom of peace".
- Act boldly, but with that Christian promptness of soul which goes hand in hand with prudence, knowledge, and wisdom. Keep Catholic faith and unity.
- Acta Apostolicae Sedis, Roma, Vaticano, 1939,1951
- Invicti Athletae, in Acta Apostolicae Sedis, (AAS) Roma, Vaticano, 1957, 321
- Hansjakob Stehle, Die Ostpolitik des Vatikans, Piper, 1975
- Stehle, 211
- J. Pastuszek, Z filozofii I psychologii komunizmu, Lublin 1938
- Invicti Athletae 29
- Invicti Athletae 33
- Invicti Athletae 34