What were the religions of famous authors?

Lapsed Catholic: What were the religions of famous authors?
What were the religions of Robert Louis Stevenson and Mary Shelley? I’ve looked online but to no avail, unless I’ve missed it. It’s for an English essay and I want to refer to the religions of the authors in my answer. Thanks.

Answers and Views:

Answer by Tapestry6
Stevenson’s parents were both devout and serious Presbyterians.
while
Mary’s folks were rather irreligious
https://www.mtholyoke.edu/courses/rschwart/hist257s02/students/Thomasena/theshiz/shelleybio.htm

Answer by Subcomandante Insurgente Steve
I can’t find anything about Shelley, but I know that Stevenson rejected his parents’ Christianity; I suppose you’d call him either an agnostic or an atheist.