What is the main religion of Czechoslovakia?

Czechoslovakia was a Federation from the end of World War 2 until 1992 when the leaders of the Czech and Slovak republics agreed to dissolve the Federation and instead form two sovereign states - the Czech Republic whose capital is Prague and the Slovak Republic whose capital is Bratislava.

This dissolution took effect on 1st January 1993. In both present day Czech Republic and Slovakia, the main religion among the population is Roman Catholic Christian with a small Protestant Christian minority.