pretty broad question. have you read any of Lewis' works?
what are the guidelines, what sort of thesis are you supposed to write...is it a biography? or are you arguing that such and such event in his life influenced some work of his?
I have read the narnia books, I have another book called "A Life" by Michael White its a biography, the essay is as I said before 1500 word minimum, I am looking at arguing how he was influential and is influential still today in his writings, I am having issues coming up with a good thesis, also thinking possibly how his influences during his life also influenced his writing
I have a thesis started, I kind of decided on my topic, how Lewis has influenced such writers like JK Rowling, Tolkien and helped them write the novels they are so famous for here is the thesis statement so far
"Modern interpretive Literature has led the way for some of the highest grossing fantasy movies ever made like Lord of the Rings, Harry Potter, and Chronicles of Narnia. The ideas for these novels didn’t just appear to these authors, they were influenced by the authors before and during their time. C.S. Lewis was one of these authors, paving the way for authors like J.R.R Tolkien, J.K. Rowling, and Sheldon Vanauken. Lewis’ Influence has created a legacy which will not soon be forgotten."
I don't think you're clear on what a thesis statement actually is. For one thing it's a statement (ONE sentence), not a paragraph.
Your thesis statement must include factual information (which you already have, for the most part) plus your position/opinion/stance. Without your position on the topic, it isn't a true thesis statement. So think of this sentence as the angle you want to take on the topic and what you intend to prove by the end of your paper. (If your statement is simply factual, then there's nothing to prove!)
This is one of the very best places I've seen online to help students write good thesis statements. It shows you sentences that aren't thesis statements and how to turn each one into real thesis statements.