Warfare and motion

The Black Death - well, a northern European perspective - is something we covered in school and keeps on appearing in the historic fiction I love. I strongly recommend Karen Maitland's medieval novel The Owl Killers, and the slightly later but still plague insightful The Witches Trinity.

But the bare facts continue to be shocking. Imagine a disease that kills millions. Without any understanding of the transmission routes, no treatments. Imagine the social chaos. The trade routes of shipping lines and the silk road were corridors for the communication of disease. What I didn't know is 'the Black Death' is a term used to describe many different viruses. Prof says that multiple plagues followed the trade routes. So that must have been scarier still: as previously known symptoms are no longer reliable predictors of a disease's progress.

• China - population drops from 120m to 80m. 
• Europe - 60% die

How does any society come back from a blow like that? Crops not planted, and then not harvested. The apprentice system in disarray meaning knowledge has died with the master of that knowledge. Children unparented. Power vacuums. Armies decimated. Abandoned by gods.