I trust that some Russian medievalists will answer for the earlier period. This answer will cover the 19th century.

The tsarist state saw Catholicism as antithetical to its vision of an empire over the course of the nineteenth century. Although it was a multi-ethnic and multi-religious polity, the Russian state saw the Western Provinces (modern day Ukraine, Belarus, and Poland) as a special area which could become Russified and reclaimed for Russian Orthodoxy. There were two main Catholic populations within the Western Provinces, the Polish Catholics and the Uniates (also called Greek Catholics or Eastern Catholics, this was an autonomous, self-governing branch of Catholicism). Especially after the 1863 Polish revolt, the state saw Polish Catholics as a lost cause for any attempts at Russification. In many respects, Polish Catholicism became a convenient scapegoat and specter for the various problems administering the Western Provinces. The state did not consider the Uniates to be a lost cause and began a policy to attempt to re-Orthodoxize them. This entailed restrictions upon the Latin script and state closures of Uniate churches and reopening them as Orthodox. Imperial officials laid the blame for the persistence of the Uniate faith at the feet of allegedly Polonized priesthood. Even by the late empire, the notion of a Catholic Russian was anathema to most of the state.

sources

Geraci, Robert P., and Michael Khodarkovsky. Of Religion and Empire: Missions, Conversion, and Tolerance in Tsarist Russia. Ithaca: Cornell University Press, 2001.

Weeks, Theodore R. Nation and State in Late Imperial Russia: Nationalism and Russification on the Western Frontier, 1863-1914. DeKalb, Ill: Northern Illinois University Press, 1996.