Why do believers feel they have to resort to forgery to try to convince others that Jesus was a real person?

Some people just need to believe in a 'higher being'. I think a prophet named Jesus lived, but I don't think that he was the result of a god impregnating a virgin. There was little written about him while he as alive. It was over a hundred years after his death that someone made up the story of Jesus being the son of god. Jesus probably never knew that.