I remember reading about an Englishman in the 19th Century who set out to research the development of Christian Doctrine and wound up converting to Catholicism. I should know his name and the name of his book off the top of my head, but I don’t.
You’re thinking of John Henry Newman. It’s not quite as simple as that, but he did write a book on the development of Christian doctrine (Essay on the Development of Christian Doctrine!) shortly before converting to Catholicism, and clearly the book describes much of the argumentation that led him to convert.
Newman is one of the greatest theological minds of the 19th century, and well worth reading.