Is It True that there was Only One True Church at the Start?

One of the biggest lies the Catholic priest is likely to tell you is that there was one true Church at the start and any other Church broke away from it.  They call the Church the Catholic Church.

There is evidence that the apostles of Jesus founded a Jewish Church and that it was Paul, a charlatan who claimed to be an apostle like them, who founded what is now Christianity. Paul had no evidence at all that he was really an apostle. That is why the Jewish Christians who survived for a few centuries dismissed Paul as a falsifier of the teachings of Jesus, who dropped the Jewish Law from his brand of religion, and was an opportunist seeking power and influence from Rome through his being a Roman citizen. This is documented in several sources, for example, The Clementine Recognitions and the Arabic Jewish Christian work found by Shlomo Pines in Syria dating from the 500's AD (page 181, The Mythmaker, Paul and the Invention of Christianity, Hyam Maccoby, Weidenfeld and Nicolson, London, 1986). Catholicism is influenced by Paul and recognises him as an apostle so it is apostate Christianity - it's not the real thing. Paul stated that nobody could obey the Law so they needed his message of forgiveness from God to be saved and be right with God. But this contradicts Deuteronomy 30:11 where the scripture says the Law can be kept. Paul was not a true apostle. His whole system was based on contradicting the Law and the scriptures while pretending not to.
 
The Jewish religion was the true religion and then Jesus came to be its latest prophet and update it and it rejected him. Thus the followers of Jesus became the new true religion. The New Testament is full of venom against the Jews and there is no justification for that. Thus the early Church clearly was apostate. There is no problem with them leaving Judaism to do what they thought was right. But when they had to resort to hatred and misrepresentation clearly they were not leaving because the Jews broke with them by refusing the updates but they were leaving just to make a hateful division. Because of that the early Church cannot be considered to have been the true Church. It was schismatic - it was not a group that was in the right that was pushed out.
 
The Gospel of Matthew is pure Jewish Christianity and urges obedience to the Jewish Law that Paul falsely claimed was only temporary. It opposes the Jews (Matthew 21:33-43) because it teaches what it would understand as true Judaism.
 
There is no evidence that St Paul got full acceptance from the apostles in Jerusalem and even the New Testament says there was disagreement. So there is no evidence that they were one Church. Paul spoke of schisms in Corinth. The faction that said it was for Kephas could have been the true Church for all we know. At the time of St Justin Martyr about 160 AD, the Church was divided between those who held that if a Christian kept the Law of Moses he was damned and if he didn’t he was fine (page 23, The Early Church).
 
Origen about 250 AD wrote that the Jewish Christians comprised about 150,000 members and was seemingly referring to new converts only (page 37, Jesus Hypotheses). The Jewish Christians were the religion the apostles founded. They claimed to have been established by the apostles with the help of Jesus' family who like Jesus were all Jews. Roman Catholicism is not the true Church because it is not Jewish Christianity.

Catholic scholar Raymond E Brown in Chapter 7 of his book, Biblical Exegesis and Church Doctrine, traced at least six different communities with different beliefs in the early Church. The early Church, if it was one Church at all, was just an umbrella. It was not a real Church but a federation of different and contradictory and sometimes sectarian Churches just like the Anglican Communion today.

Anyway the early Church being one is not important. What is important is did it preserve Christ’s teaching intact? The Church has to err to some extent.

Unity with the Church of yesterday

It is not enough for the Church to be one with and in the membership alive now but it also has to be in communion of mind and heart with the Church that has gone before. If it creates new teaching it ceases to be the same as that same Church and unity is broken. The Catholic Church has invented new infallible teachings so it has broken with the Catholic Church of old leaving two Churches.

Some believe that when the Church of Rome added twelve new dogmas in addition to the old creeds in 1564 without the consent of a proper council and even added articles of faith to the body of the old creeds that it broke away from real Catholicism (page 7, Why I Am Not a Roman Catholic, PTS).

A serious problem
 
It is incorrect to say it is enough for the Church to be one. You have to prove that it SHOULD be one. Unity cannot impress or be a mark of divine favour if the seeming unity is gained by compromising your conscience which must happen in the Roman Church to a huge extent. The Roman Church says that if she issues an unjust decree of excommunication the excommunication is null and void which should lead to chaos. The law of the Church then does not promote unity and if the Church were really Catholic and one God would make sure it does. The Bible itself commands that causing a schism may sometimes be necessary to preserve the true religion. The Jews had to break with the Samaritans over the latter altering doctrine. It is unfair to use the argument from oneness without first proving that there has been no departure from the deposit of revealed doctrine. The Roman Church has been altering doctrines these days which implies that it is time that the Reorganised Roman Catholic Church be set up to continue the old faith. The pope cannot preserve unity for the validity of his authority depends on his intentions and orthodoxy. A heretical pope is not a pope at all.