Origin: The origin of Christianity dates back thousands of years before Christ when prophets predicted the coming of Christ. Jesus is the founder and main prophet. Jesus spread the words of god. It is the largest followed religion in the world. (33% of the world.)
Major beliefs: Major beliefs are that Jesus died for humanities sins and that people are saved for eternal life by faith in Jesus Christ. Another major belief is that God created the Earth for all humans and animals. Also that Sunday is a day of rest in the week. The Bible is the holy book of Christianity.
Various sects: The major sects of Christianity are Roman Catholicism, Eastern Orthodox, and Protestantism. Although there are many sects of Christianity those are the most common and major of them.
Holidays/Celebrations: Christmas, Good Friday, and Easter. The holidays and celebrations celebrate the life and death of Jesus Christ.