Can you tell me a little bit about Christianity?

Christianity is one of the three Abrahamic faiths and members of this religion follow the teachings of Jesus Christ as described in the New Testament of the Bible. Jesus of Nazareth was a rabbi from the Galilee region of Israel and believed himself to be the son of God. As the narrative has it, Jesus was born to a virgin mother and committed no sins during his life. Because he was the son of God, he was able to live a life free from sin and totally in accordance with God's intention for humankind. In addition to preaching publicly and performing miracles, Jesus issued a new commandment to the people of Israel to be followed in addition to the ten Mosaic commandments. At the time, many people were technically following the ten commandments communicated through Moses but were otherwise unkind or unjust to each other. Before being put to death for claiming himself to be the son of God — and having gained followers who believed this about him, too — Jesus urged his followers to treat one another as they wished to be treated and to love their enemies. 
Christianity has transformed quite a lot in the nearly two-thousand years since it has gained a following. Early on, Christians were considered to be a weird bunch of people because they broke with many Jewish traditions like ritual sacrifice of animals and circumcision of infants. In the year 312 CE, the Roman Emperor Constantine converted to Christianity and issued official laws demanding tolerance of Christians. His actions helped transition the Roman Empire from a patchwork of Jewish and indigenous folk traditions to a fully Christian territory. Throughout European history, the religion of kings or warlord rulers has generally served as the official religion of the people they rule. Christian kings like Charlemagne and Louis IX helped preserve Christianity in the West even after the fall of the Roman Empire.
Today, hundreds of Christian denominations exist. The largest Christian denomination is Roman Catholicism. There are also Protestant sects, including Baptists, Pentecostals, and Lutherans. The reason for so many variations in Christian practice is that, over time, people have continued to interpret Scripture and the teachings of Jesus Christ and have come to disagree over some meanings and practices within the Church. 
http://www.religioustolerance.org/christ.htm

https://carm.org/what-is-christianity

https://www.allaboutreligion.org/history-of-christianity.htm