Couldn't a religion start pretty easily with just a combination of charisma and deceit, or charisma and mental illness, in a tribal leader? If the community trusts a person, and that person makes supernatural claims, what is stopping other people from believing that person? What is stopping those claims from snowballing into a text, into a body of worshipers, into a religion?
All that needs to happen is for the leader to either (A) truly believe he experienced something supernatural or (B) see a benefit in other people believing his supernatural claims. There are many reasons a person would believe they were a disciple of god: mental illness, sincere confusion about some kind of event, etc. There are many reason a person would want others to believe they were a disciple of god: money, power, respect, etc.
Follow-up: If your answer to the title question is "Yes", then how can you be confident that Christianity was not contrived in that way?