Magnum Crimen
Josip Juraj Strossmayer's ideas, of which the most important one was - serving God equals to serving people, created close relations between Croats and Serbs by introducing the Old Slavonic language as the liturgy language of the Roman Catholic Church in the Balkans - were aggressively suppressed by the Roman Catholic clergy in Croatia and Slovenia.  The clergy put the Roman Curia in between the God and the people, demanding from the Roman Catholics ultimate obedience to the Roman Curia and unconditional love of the Roman Pope. The clergy remaining faithful to the Strossmayer was marginalized, with the most ardent supporters excommunicated by the Zagreb archbishop.