Thank you, this is really helpful! Because I knew the general outlines, the big picture politics, and I had some clue that filioque was to do with the exact nature of the Trinity, but here you've filled in some of the personalities and their motivations. Also it's a clearer explanation than I've ever come across before of what the language problem actually was, the way you provide both Latin and Greek and gloss them makes me feel like I get what the schism was about.

Also I'm glad that you included the ecumenical stuff from the twentieth century, cos for one thing that's more encouraging than just a millennium of bickering between eastern and western Churches. I'm interested in Catholic / Orthodox unity in general too, partly because of the Hengrave connection, and partly because it's really fascinating to see such huge institutions addressing such a long-standing division.