The First World War (1914-1918) brought these processes to a head. After the end of the war the reforming priests asked the Papal See for understanding of their attempts at reform within the church, but in vain.

The founding of the independent Czechoslovak Republic in 1918 encouraged the reforming priests, who were organised in an association called "Focus" led by Roman Catholic priest Karel Farský, to actively implement their reforms.

At Christmas 1919 they celebrated the whole of the church service in the Czech language for the first time.

This met with such widespread enthusiasm in all sections of the population that it led to the setting up of a separate church, independent of the Papal See in Rome, on 8 January 1920.

The independent existence of the new church was publicly proclaimed by Dr. Karel Farský in the church of St. Nicholas on the Old Town Square in Prague on 11 January 1920.

Credo was authorised by Assembly of Czechoslovak Hussite Church in 1931.