
Every now and again we get glimpses of the Sultan’s brilliance, showing him as more than the often naive and childish old man portrayed in much of the movie and throughout the series. This episode takes place just after the Sultan’s marriage to his wife – likely when he was still a prince and not a Sultan at all. (And God, I wish they had revealed his actual name.)
So this intro scene, while presenting our antagonist, Arbitus (voiced by Ron Perlman, if you can believe it), also shows us the sort of prince that the Sultan was in his youth.

First things first: we see him out exploring – just for the Hell of it apparently. Just after getting married. Perhaps he was looking specifically for this place because the Sultan, however innocent you see him, has always displayed a fascination toward magic. Anyway, I don’t think he’s the Sultan yet, and given that this flashback takes place twenty years before the series and his hair has gone completely white in the meantime, I want to place him in his thirties in this scene. At the earliest.
That may seem kind of advanced in age for him NOT to be the Sultan yet. Given his general naivete about things, the fear of conflict he shows in this flashback suggests to me that he might not be the eldest or only child of the royal family and was likely very sheltered. The baby of the family, even. My money is on him having an older sibling, and he never personally expected to take the throne, but then there was an unfortunate death in the family sometime after this point.

I didn’t view this as necessarily cowardly. I think he’s afraid but I also think the Sultan is and always has been the sort of person who hesitates to do harm to anyone and he just happened to do something thoughtless and ignorant in this one instance.
But let’s rewind a little so we can get to that. He discovers a castle made of plants in the desert:

This would indeed be a considerable wonder to anyone dwelling in a desert climate. I hesitate to assume the Sultan was just ignorant enough to think this place didn’t belong to anybody and just wandered right in.

Even if that’s totally what it looks like.
I like to think he might have come looking for this place. But I’ll get to that in a second.

He explores the wonders of the garden, including living musical instruments, apparently.

And then he decides he wants this flower. He picks it, incurring the wrath of the Garden’s protector. Meet Arbitus, who in the wikipedia page is described as a “sorcerer” but my money here is on “Earth Elemental” since he appears to be quite literally made of the earth and flora, himself.

He refers to the flower as his “masterpiece” because the garden is basically a giant art installation. He creates living art. The Sultan begs him to spare his life, explaining that he only wanted to bring a flower to his new bride. He promises that his greatest treasure will belong to him if he lets him go. Arbitus promises he will come for said treasure in twenty summers.

So several things: I think the Sultan wanted to prove himself worthy to his bride and went somewhere that was rumored to be dangerous to bring her something special. That’s the sort of thing heroes do, right? And what is more heroic than a prince?
Also this is probably why Jasmine is named after a flower. And why the gardens in the palace are so expansive and well-cared for.
I really want to know more about his life before Jasmine was born, so I’ll just have to go with the ideas until something better comes along.