What about the churches that existed BEFORE 1,600 years ago, i.e., the Assyrian, Chaldean, Coptic, Armenian, Georgian, all of which still exist today? They are "denominations" meaning organizations of local assemblies. AS is the Rome-Centric Catholic Church.
All of the Catholic churches are basically in communion with one another. None is older than the Roman church because that is where Peter went and where he was crucified.....The Eastern rite Catholics are in every respect Catholic and again, the protestants did not come into existence until Luther showed up...