Fantasy book with pontifex and travel across large planet.

Read it in the 80's I think. A group of travellers travel across a large very populated planet ( I remember that was stressed a lot). Turns out that one of them is the heir to throne who has lost his memory (poss). There was a sort of double rule arrangement with a young ruler and an old ruler (the pontifex) who was being kept alive artificially.

Probably not the one you're after as it's only a very loose fit - but your description reminded me of Beyond the Hanging Wall by Sara Douglass

Sounds like Lord Valentine's Castle by Robert Silverberg.

"Majipoor is a planet much larger, though far less dense, than the Earth."

"...the previous Coronal retires to become the Pontifex..."

Definitely sounds like Lord Valentine's Castle. It matches on every point. A very good book.

Yeah, when I saw Pontifex I immediately jumped to that series. There's quite a few books (4-5?) in it now - the trilogy that began with Lord Valentine's Castle, a few prequels, possibly some sequels. I read the trilogy then stopped.

Agree - the Majipoor Chronicles are excellent if just a little long winded, (a total of 9 books). But the trilogy are easily stand alone reads.

Lord Valentine's Castle - that's definitely it. Many thanks!