Many studies have focused on the autonomous functions of the Catholic Church under the communist regime in Poland in comparison to other countries in former Eastern Europe. The autonomy of the church is sometimes confounded with the resistance or struggle against the communist party, although the church did not necessarily attempt to fight against the party with concerted effort. Obviously, the church is not a monolithic organization; it has to distinguish the general believers that account for most of the Polish from the leaders of the church. This paper examines how believers became involved with “the struggle, ” referring to the concept of the “collective mentality” proposed by George Lefebvre. He explained that some affairs were composed by the people, who gathered even accidentally, but because of their “collective mentality” they are capable to change the character of the activities into social and political affairs without conscious awareness.<BR>I will look, for instance, into an affair that occurred during the establishment of a parish church in an industrial estate around the Lenin Steelworks. I analyze what “collective mentality” was underlying, and how had been changed among people. For 12 years, people in this estate had moderately appealed to the party and to the administration to permit them to have their own church for practical reasons i.e. it was inconvenient to go to other churches as they were too far away, and they did not want to participate in a Mass in the snow and rain outdoors. Meanwhile they had come to clearly distinguish between the party and themselves.<BR>Generally, the affair has been recorded as a violent confrontation between the party and the church for freedom of faith. However, the believers that joined in the battle on the street said that at the beginning they only wanted to defend and keep their own cross, which they had built as a symbol of their faith. They changed their attitude gradually because of escalation of violence, and the reaction of the authorities; consequently, many of them began to agitate for freedom of faith and other political ideals. In the process of escalation, however, we can observe some accidental factors, for example misunderstandings, miscommunications and so on. After the incident, clergymen suggested that the battle had been a political fight from the beginning and the believers were motivated by political and social reasons.<BR>This case demonstrates how Catholics participated in and were involved in the political field. There were some disconnects between the clergymen and the believers; both had their own stories and values. However, we can say that people shared a “collective mentality” through their relationship with others; that is true not only for the communist party, but also for the leaders of the church. And now the shared “collective mentality” is changing in relation with the others: the different generations, some foreign journalists and us-researchers of history.