Susa is one end of the great royal highway that goes from Sardis all the way to Susa right over there. You have Darius the Great, establish a capital at Persepolis, and that's the Greek name for it, literally referring to Persian city, and this is a relief from Persepolis right over here. Now, the end of the Achaemenid Dynasty comes when that famous thorn in the side, Greece, actually unifies under Philip of Macedon, and here we're talking about the early to mid fourth century BCE, and his son Alexander becomes this great conqueror, Alexander the Great, and he's able to conquer the entire Persian Empire, famously taking it away from Darius III. We talk about that in another video, or in several videos in some detail. But Alexander the Great, he has this vision of a one nation, of these people, kind of their cultures mixing together, and there's a significant amount of cultural mix between the Greeks and the Persians, but then Alexander dies and his empire is split, but most of the Persian Empire goes to, under the control of Seleucus, who's one of Alexander's generals, and then you have the Seleucid Empire, which is really foreign rule of Persia, and that will continue for a while until eventually the Parthians, which is once again another state or region of the Persian Empire, takes control to establish the Parthian Empire, which is one of the rivals to Rome. That's worth mentioning, and I mentioned this in the video on ancient Persia, that under Persian rule, and Cyrus, and the various Shahs and Shahs, they were famous for delegating their authority. When you have such a large empire, you can't control all of it yourself, so each of these regions had their own, I guess you could say, governors, and those governors were called satraps, and the regions were called satrapies.