So each region, each satrapy had its governor called a satrap and as we see over time, some of these satraps got more power than maybe was intended and then eventually took over but this was a major empire in the history of the world. They unified people. They're famous for the royal road that connected Sardis all the way to Susa. As you can imagine, it would have facilitated the transfer of knowledge and the transfer of trade. Under the Seleucids, you had huge Greek influence but it was a two-way street. Not only did the Greeks influence the Persians but the Persians heavily influenced the Greeks. So with that, in the next few videos, we'll go into even more depth on the Persian Empire and specifically, the Achaemenids.