Who is the founder of cristinanity?

Ultimately, the founder was Jesus Christ. However, one could also argue that it was the apostles of Christ who preached the teachings of Jesus. Jesus never said "I want to make a new religion and it will be called Christianity". It is important to understand that Christianity is seen as a renewal of Gods covenant (agreement) with the Jewish people, and therefor stems directly from it. In order to understand the fullness of Christianity, you must have a basic understanding of Judaism. The "New Testament" should also be seen as a continuation of the Jewish Bible or "Old Testament". Like most things, Christianity has had organic changes throughout its history and has grown into what we see it as today