How did Christianity begin and why was Jesus killed?

Christianity is the most widely practiced religion in the world, with more than 2 billion followers. The Christian faith centers on beliefs regarding the birth, life, death and resurrection of Jesus Christ. While it started with a small group of adherents, many historians regard the spread and adoption of Christianity throughout the world as one of the most successful spiritual missions in human history.

Christianity began in the 1st century AD as a Jewish sect in Judea, Roman province but quickly spread throughout the Roman empire. Jesus died to atone for sin to make us right with God.