In addition to the mainly Orthodox countries such as Bulgaria , Byzantium and Serbia , there were a number of Catholic possessions to the west and south held Defending by Venice , Genoa and the Kingdom of Hungary as well as Kingdom of Bosnia whose Bosnian Church ( closely related to the Bogomils ) was considered heretic by both Orthodox and Catholics .

The rebellion was in equal part a protest by feudal lords against the intrusion of central government into their domains ; a conservative Irish reaction Response to English policies that were altering Change traditional Gaelic society ; and a religious conflict Hostile_encounter , in which the rebels claimed Statement that they were upholding Catholicism against a Protestant queen who had been pronounced Statement a heretic in 1570 by the papal bull `` Regnans in Excelsis '' .