And so you might say, well, why doesn't that process just keep on going on indefinitely? Well, it does go pretty far. You see these various empires are quite large, especially when you consider the technology of the time, the communications ability of the time. But at some point, you might have weak leadership. You might have trouble controlling these large and spread out empires, especially if you can't communicate, if you can't get good information. But now let's dive a little bit deeper into the four empires we just referred to. So let's start with the Cemetery of Persia, founded in 550 BCE by Cyrus the Great.