Question: what is most likely the most important council for the roman catholic church

title: Traditionalist Catholicism
text: The De-Latinisation of the UGCC gained further momentum with the 1964 decree Orientalium Ecclesiarum of the Second Vatican Council ) and several subsequent documents . This resulted in the Latinisations being discarded within the Ukrainian diaspora . The Soviet annexation of Western Ukraine had meanwhile forced Byzantine Catholics into a clandestine existence and the Latinizations continued to be widely used in underground parishes , seminaries , and religious communities . After the prescription against the UGCC was lifted in 1989 , numerous UGCC priests and Hierarchs arrive from the diaspora and attempted to enforce liturgical conformity . This has provoked widespread opposition . SSPX