How old is Earth? Did dinosaurs exist?There were definitely other religions before Christianity.
I already posted the Letter of Saint Ignatius of Antioch dated from 110 A.D. where he mentions the "Catholic Church."
The word "Catholic" means "universal" in Greek. It's the original Christian Church.
Jesus was definitely Jewish. He was the Jewish Messiah who opened up Judaism to the whole world, including gentiles, which is the Catholic Church.
That's the "good news" of the Gospel.
(I don't expect to convince anyone.)