Is There a Connection Between Christianity and Theism?

I had a two-step conversion but was converted first to theism and then separately in a sense to Christianity and Lewis was really important with that that second step. I think it's a little bit more complex than that as well because I think that what he felt was a vast sense of of longingwhat he calls joy and is not about biography and he was looking for something that would satisfy that. He didn't think that anything could satisfy it and yet magically he still had this feeling, so eventually he realized that philosophically and rationally theism made sense and so he got part of the way there. What drew him in in the end was that he realized not that he was looking