The origin of Christianity is not really mentioned and it is from the time of Jesus and the Pentecost. First Christian is those who follow Jesus his apostles and disciples.
Jesus developed Christianity from the day he died, his disciples and followers continued that in the country of Israel, which over the years spread into the Roman army and throughout their empire across europe
Read the Book of Acts in the Bible. This is where Christianity began. See also question "Why did Christianity originate"
Christianity can be said to have started with Peter's preaching on the Day of Pentecost, in AD 30, in Jerusalem.
The date for the origin of Christianity is Pentecost in 33 A.D. with the coming of the Holy Spirit upon the Apostles.
Christianity became the faith of the followers of Jesus Christ from the year 33 AD when Jesus established His Church in Jerusalem on the Day of Pentecost.
Jerusalem
Jerusalem
The place of origin of Buddhism was Nepal, India while the place of origin of Christianity was Jerusalem.
Roman Empire. As the Jewish lands where at this time occupied by this Empire. Modern day middle east.
Christianity is one source.
jesus's birth
Christianity stared in Israel. After the death of Christ.