Are educational documentaries impossible to track down?

File: 1455667193570.jpg (53KB, 604x604px) Image search: [Google]

53KB, 604x604px

I remember that, growing up, one of my absolute favorite things to do was to watch historical documentaries, films, and educational shows on channels like the History Channel (you know, before they became the Alien Hitler Riding Dinosaurs channel). I've recently found myself wanting to watch more content like this (in particular educational films on the European dark ages and early medieval era) but no matter where I look I can't seem to find it anywhere.

Is there really just so little demand for this kind of content that you can't even find it on common streaming services? That's not even to say anything about seeing new content made, just finding the old stuff seems like a near impossibility unless you want to watch something about WWII or the 70's.