Jesus is literally in the middle of the three monotheistic religions: Judaism, Christianity and Islam.

Judaism
Jesus was a Jew himself, who grew up in the Judaistic tradition. In the Torah, which consists of the holy books of Judaism, it is predicted that a prophet would come ´greater then Moses´. This is 'the Messiah' or 'Christ'. Jesus claimed to be this Messiah and is therefore called 'Jesus Christ'. Nevertheless, mainstream Judaism, untill this very day, never accepted Jesus as their Messiah.

Christianity
Jesus is the root and the heart of Christianity. Jesus did not want to start another religion. He called himself the fulfillment of the Judaistic covenant, but he was basically rejected like that and even killed for it. He called himself the ´son of God´ which was considered to be blasphemy in that time, because it meant that he called himself to be God (in a similar way as a 'son of humans' is of course human...).

After his death his followers wrote down a lot of the literal things he said and had teached. They constructed biographies based on that, of which we have three written reports left, that therefore look very similar. A fourth report has been written by one of his closest friends at the end of his life, which gives a very different, much more personal view at the person of Jesus.

The biggest event that Jesus´ followers where talking about is that they claimed that Jesus rose from the dead after his crucifiction. They where so determent in this that they where ready to die for it, exactly as Jesus had died himself.

Another thing that Jesus spoke about was that God would give his Spirit to live in ordinary people. These two things: the claim that Jesus rose from the dead and the Spirit of God filling people, made that christianity explosively grew against all prosecution. Within the first century there where about a million christians. Around the year 300 there where between 5 to 8 million, which is a 'growth rate' of 40% per decade.

The writings of his friends and followers in the first century are called 'the New Testament'. Together with the Jewish Torah, which is also completely accepted as 'the Word of God', this is called the Bible.

Islam
About 500 years later the prophet Mohammed came. He wrote the Qur'an, which was dictated by the angel Gabriel. It also mentions Jesus as a prophet. Islam says that the Torah and New Testament are corrupted texts. The only way to interpret them correctly is by comparing them with the Qur'an, which literaly came out of heaven and therefore has no faults. This means that Jesus is not a 'son of God' since there is just one God and not three (The Father, Son and holy Spirit). Also Jesus did not raise from the dead, but was taken into heaven before he died.

The problem with this is that history is rewritten 500 years after it happened. If you want to know what happened, the best thing is to go as close as you can get to the source.

Summary
The story of christianity is basically this: God is writing human history, because he is concerned about us and wants to partner with us. Fallible human beings (but nevertheless inspired by God's Spirit) have written about the things God has done. The biggest stunt God has undertaken to reveal his true character to us, is that he has become a human being... one of us! And the name of that man was... Jesus. Jesus is like... the human face of God, so we can more easily relate to him, understand him, know him... love him back for the love that he has shown to us...