The ultimate authority is divine. Earthly authority is limited to protecting the deposit of faith, not creating a new religion. The fierce in-fighting on this site on these matters shows the line is being drawn between two religions, both claiming to be Catholic. One side is led by a Pontiff in love with novelties who disdains the teachings of his predecessors, the other adheres to the practices and teachings of popes, councils and saints that have been transmitted over a span of two thousand years. The two religions are irreconcilable. Only one is the true religion.
One is led by the Vicar of Christ on Earth and the other (SSPX) is led by a cesspool of defiant and disobedient schismatics bent on destruction of Holy Mother the Church. The Roman Catholic Church wins. It was in all the bibles.