The Catholic Church had a significant influence both among the Ukrainians and Poles. The level of the population's religiosity was high, and the church leaders were of great importance in the social and political life of both communities.

The Greek Catholic Metropolitan Andrey Sheptytskyi (1901-1944), a count, came from the Galician aristocracy. He enjoyed a high level of trust among the Ukrainians of Galicia. He was the greatest patron of Ukrainian culture and education, the founder of the first modern Ukrainian museum in 1913. His authority grew particularly after his return from Russian captivity in 1917.

The Roman Catholic Archbishop Józef Bilczewski (born Józef Biba) was a professor and rector of the Franz I University of Lviv. As Archbishop of Lviv (1901-1923), he made much effort to revitalize religious life and was a well-known philanthropist. During the Ukrainian-Polish war, the two archbishops were on different sides of the barricades. However, the residence of Sheptytskyi was located in the part of the city controlled by the Poles, and the residence of Bilczewski was on the Ukrainian side. Sheptytskyi and Bilczewski also were in radically different positions as to the causes and the course of this conflict.

The Roman Catholic Archbishop accused Ukrainians of starting the war and committing crimes against the Polish population. In his turn, Metropolitan Sheptytskyi supported the aspirations of Ukrainians for state independence and considered the Poles guilty of inhuman attitude towards Ukrainians. Despite the differences, from the first weeks of the war, Bilczewski and Sheptytskyi tried to help the socially vulnerable city residents. They also initiated talks on a truce and appealed to military commanders encouraging the latter to exchange prisoners.