Upon accession to the patriarchal throne, he moved his seat from Urmia to Salmas, and also resided in Khananis near Qodshanis.
He succeeded Patriarch Shimun IX Dinkha who was in full communion with the Catholic Church.
Unlike his predecessor, who was officially recognized by Rome as the Patriarch of the Chaldeans, Shimun X was not formally recognized by the Catholic Church because his election was based on hereditary principle, reintroduced after the death of his predecessor.
Upon examination, Shimun′s profession was found inadequate, and he was not received into communion with the Catholic Church.
Because of such complex situation, his legacy was viewed differently along denominational lines, and claimed by both sides.