Contrary to the popular belief many Indians have , that it was brought by the Portugese, Christianity had its roots in India even before England and Ireland heard about Christ. Though it is widely believed that it was introduced to Kerala within a century of Christ's death , by St. Thomas, one of the apostles of Jesus himself; it can be confirmed that the advent of Christianity was established in India by the 6th Century A.D. Kerala always had a substantial population of Jews in its coastal areas , particularly Cochin and most probably they were the first converts to Christianity because of the language affinity.
And it may also be noted that the first mosque of India, was supposedly built in 629 (during the life of Prophet Muhammad) in Kerala. Many won't believe this but this is a fact and there is nothing to be surprised about it. Even before the religion of Islam was established by their Prophet Mohammad , Arab traders were in contact with India. Merchants would regularly sail to the west coast of India to trade goods such as spices, gold, and African goods. Naturally, when the Arabs began to convert to Islam, they carried their new religion to the shores of India.
So those who believe or want us to believe that both Islam and Christianity are alien to our country may please note that it is more integrated with our country and its culture than USA, England, Russia,Australia and China. Those who believe in any religion can let others practice their own religion, in peace without doubting their nationality, intention or purpose. But it's much better not to take any religion seriously. They are all controlled and propagated by vested interests.
Also people should note that our history did not start with the establishment of or freedom from the British rule. It dates back to many centuries . Much of it may be myths but nevertheless the study of recorded points of history can dispel many misconceptions that we have in our mind.