"Christianity," as an identifiable separate religion, doesn't actually have a birthday in spite of the fact that we usually celebrate Pentecost as the birthday of the church. In fact, the Spirit-filled followers of Jesus remained an identifiable sect of Judaism for many decades. Most of the them were Jewish, and one powerful wing of the "Way," as it was called, believed that only Jews could be his followers. Over time, however, the rest of Judaism found the Way less and less acceptable while more and more of Jesus' followers weren't Jewish; and eventually the Way became a separate religion, Christianity. This took time. It is not correct, for example, to call the Apostle Paul a Christian. Christianity as an identifiable religion didn't exist yet, and it is clear from the New Testament that Paul considered himself to be a practicing Jew who believed that Jesus was the messiah (Christ). The point here is that the church evolved from being a Jewish religious group with peculiar (but still Jewish) beliefs about Jesus of Nazareth into an identifiably separate religion with Jewish roots. It took time for us to go through this process of separation.
Conversely, the 19th century western Protestant missionary movement preached a message that called on people of other faiths and cultures to convert to Christianity and become, virtually, a part of the western church. Converts were expected to reject their previous religion and join churches that were like western churches. They sang western hymns translated into the local language. They sat on pews. Nothing in the church was borrowed from their former faith. Unlike the early church, which only gradually separated itself from Judaism, convert churches formed by the Protestant missionary movement were expected to make a swift and clean break with their past, and they were ex that there had been anything good in that past. In many nations, the consequence was that most people refused to make such a break even if they were otherwise attracted to faith in Jesus. Leaving their former religion so abruptly created tensions with neighbors and other family members, and it meant giving up much in life that was comforting and familiar.
In the past, Protestant missionaries simply insisted that a hard break had to be made, many still do. But, in various parts of the world there is a movement of sorts to create churches that do not make a hard and fast break with their original faith and its culture. Although not stated as such, the goal is to replicate more nearly the experience of the early church by making a gradual separation from one's previous faith and to dispense with hard and fast boundaries between religions that have to be crossed in a single leap. The Hindu religious movement,Yeshu Satsang, is one such attempt to come to Christ more gently, less abruptly, and with less conflict. In a posting entitled, "Following Jesus Yet Still Hindu or Sikh? Mission Leaders Weigh In on New Communities," reporter Michelle A. Vu describes how Yeshu Satsang communities have emerged as a way for Hindu and Sikh followers of Jesus to remain fully Hindu or Sikh as they explore and develop their faith in Christ. They worship in ways that make sense within their own culture. They've adapted the sacraments to fit that culture. They sing songs that are Hindu and Sikh, and the members of Yeshu Satsang "churches" will sometimes insist that they are not Christians (i.e. members of a foreign religion) but remain Hindu or Sikh. It's just that they follow Jesus.
That's worth thinking about—being a follower of Jesus but not a Christian. That's what Paul was. Peter and the other disciples all died before there was a Christian religion. They followed Jesus while remaining devout, practicing Jews. One of the things that seems to be happening in our increasingly secular society is that small groups of followers of Jesus are reinventing the church in ways that make more sense in the 21st century than do traditional churches. Maybe something we should be aiming for is to be more Christ-like and less Christian. Worth a thought.