The earliest records would suggest the Romans brought the religion to Britain.
christianity
christianity islam judaism sikhism
A change of heart and life are the greatest evidence of the reality of Jesus Christ! R. Ishmael
Missionaries
By 325ad Christianity had spread throughout the Roman Empire and to Britain. If you google "spread of Christianity map" you will find maps showing the spread.
A large variaty; but Christianity is popular and always has been in Britain.
No. He was not Irish. He came from Britain and brought Christianity to Ireland.
Yes. Evidence seems to suggest that Jesus was Jewish. Christianity and branches of Christianity were actually formed from the foundations of Judaism.
Pope Gregory the Great
The Anglo-Saxon religion immediately died out
Science defines a theory as a hypothesis that has strong and verifiable supporting evidence. With no strong and verifiable supporting evidence, Christianity remains a hypothesis. ~ Sorry to disagree with the OP, but to say that disregards any of the evidence from Scripture and other ancient literature, as well as archaeology. It also precludes the acceptance of testimonial evidence, which is an important source of evidence in the courtroom. Although I think it would be more applicable to call Christianity a philosophy or worldview rather than a theory or hypothesis, Christianity is primarily a relationship between God and man through the person of Jesus Christ. A Christian follows the ways of Jesus, having received grace and hope from Him. A matter of faith, yes - but it is faith that brings about the results and therefore evidence in one's own life. I for one have a much different life because of Jesus, so to say there is no evidence is plainly incorrect in my case.
There are no historical evidence that Jerusalem was ever the center of Christianity. Most activities of the early Christians happen in the country of St. Paul, in Turkey.