Christianity
Christianity started out as a breakaway sect of Judaism nearly 2000 years ago, 30+ CE.* Jesus, the son of Mary and her husband Joseph, believed by Christians to be conceived through the Holy Spirit, was bothered by many of the laws and practices of his native Jewish faith and began preaching a different message. During his travels he was joined by Mary Magdalene and twelve disciples who followed him in his journeys and learned from him. He reportedly performed many miracles during this time and related many of his teachings in the form of parables. Among his best known sayings are to "love thy neighbor" and "turn the other cheek." At one point he revealed that he was the Son of God sent to Earth to save humanity from sin. This he did by being crucified on the cross for his teachings. He then 'rose from the dead' and appeared to his disciples and told them to go forth and spread his message.
Since Christianity and Judaism share the same history up to the time of Jesus Christ, they are very similar in many of their core beliefs. There are two primary differences. One is that Christians believe in original sin and that Jesus died in our place to save mankind from that sin. The other is that Jesus was fully human and fully God and as the Son of God is part of the Holy Trinity: God the Father, His Son, and the Holy Spirit. All Christians believe in heaven and that those who sincerely repent their sins before God will be saved and join Him in heaven. Belief in hell and satan varies among groups and individuals.
There are a multitude of forms of Christianity which have developed either because of disagreements on dogma, adaptation to different cultures, or simply personal taste. For this reason there can be a great difference between the various forms of Christianity they may seem like different religions to some people.
'If you cannot see God in all, you cannot see God at all.'
*The dates are given in BCE (Before Common Era) and CE (Common Era). These years correspond to the same dates in BC and AD but by defining the current period as the "Common Era" the nomenclature attempts to treat all religions and beliefs as equal.
