Polyamorous Messiahs From Mars

I read Isaac Asimov's Foundation trilogy back when I was in high school. It must have not made much of an impression on me, because I don't remember that much about it, at least not like other science fiction books I read back then that seemed to stick with me a lot more, for whatever reason, like Stranger In A Strange Land....

Must be something about "polyamorous" messiahs from Mars that sticks with you better than dry scientific eons-spanning psychodrama. Especially if you're a high-schooler.