Wiki'd World 1: King of Wishful Thinking

I thought I'd start putting up quiz questions, but I figured that's not much fun on the internet, because all one has to do is Google the answer. So instead, I'm going to try this – I put up some obscure bit of trivia, and the objective is to get whoever who reads this (all 3 of them) to go off and read up on Wikipedia and/or elsewhere on it. Hopefully it will make for interesting reading. If I'm lucky I might even get some feedback on this and I might put up an update later.
Anyway, here's the first post. The image below is from Neil Gaiman's Sandman series of comics about the Dream Lord (he's the one in the black outfit with the black speech balloon) (issue #31). The guy that Dream's speaking to is Joshua Norton, who was a real-life personality. So the question is: what happens next?

Incidentally, if you get a chance, do try to get your hands on the comics, or indeed any other comics written by Gaiman. His stories aren't half bad either, though I think he's got the same problem that Philip K Dick had – he writes quite a bit, so not all of the work is consistently good. It is consistently different though, which is a good thing if you're bored of what you've been reading.