I don’t know The Collector, having only recently been alerted to it by Google, but their article entitled Rise of the Sasanian Empire: The Persians (205-310 CE) looks interesting. I have not had a chance to read the article in detail, but it looks generally good and offers photos to illustrate the art and archaeology of the empire.
The site brings you ‘Daily Articles on Ancient History, Philosophy, Art & Artists by Leading Authors. Trusted by Scholars, Classrooms & Enthusiasts’. They have articles on the Achaemenid kings, Cyrus The Great, the Parthians , Zoroastrianism and even on The “Communists” of Ancient Iran: Mazdak and the Khurramites.