What Will Thalaba Destroy?

It took me a few pages to get into Thalaba or understand what was more or less going on, but at some parts it really sped up and easier to at least understand on the surface what was happening. I'm not sure if Southey was directing writing about Islam or just a made up religion similar to it since there was the Prophet but his name was Houd? I also wanted to know what the other clouds would have done had the messenger picked the red or white one. All of this may have been in the apparently extensive footnotes, but I lost my course pack so I read it on Google Books. One thing that kind of bothered me was the extremely long speech by Aswad. Even if I was trapped in solitude for a thousand years or something, I don't feel like I'd have to energy to explain my whole life story in one breath. It was just too long-winded for me, I needed some breaks or pauses in there. But back to the Islam thing, I'd like to know more about how much Southey really knew about the religion, and how accurate it would've been if this is a commentary on it.