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 occupation of Western Ukraine had meanwhile forced Byzantine Catholics into a clandestine existence and the Latinizations continued to be used in the underground. 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.