Sci-fi where Alexander the Great conquers a ringworld

I read this sci-fi novel around two decades ago. It takes place in distant future where humans and various alien races somehow take various historical figures from the past and make them wage war and then bet on it.

Most of the story follows Alexander the Great and an alien warlord on a ringworld. Humans living there are underdogs because they're physically weak compared to the aliens, but Alexander teaches them to do the phalanx and conquers vast swaths of the ringworld.

And outside that the story went that some human bet a lot on Alexander and became filthy rich but I don't remember this part very well.

I'm just sure it wasn't Larry Niven's Ringworld series although it might've been inspired by it since it took place on a very similar world.