PROVE that Catholicism was the ONLY church for 16 centuries. PROVE that no other people existed. Or stop saying it. If you cannot prove it, you cannot state it as fact. And have any respect.
The world is full of Catholic churches, monasteries, schools libraries, hospitals,which date back to biblical times...there are no other Christian denominations there at all. Obviously there were pagan religions, and religions who did not recognize the God of Christianity....but that's not our discussion....the Catholic church was the ONLY Christian church for about 16 centuries....I Can't prove that there were no others, that would be proving a negative....if there were 0thers (there weren't) then you prove the positive....their sect, buildings, accomplishments, history, followers, leaders, proclamations, teachings....whatever.