Concept
Version 3
Created by Boundless
Ivan the Terrible
Source
Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:
"Ivan's Ivory Throne."
https://en.wikipedia.org/wiki/Ivan_the_Terrible#/media/File:Ivans_ivory_throne.jpg
Wikipedia
CC BY-SA 3.0.