re: Medieval battles

I didn't pull them from my arse lol. Ive seen it discussed multiple times in books and articles and read the casultiybfigures for battles.

If you want a specific book:

Ghenghis Kahn and the making of the modern world goes into this when talking about the Mongols encountering Georgia. Knights.

Also, was recently about the 30 Years War where they talk about how gunpowder changed the battlefield and made the old formations useless and it went into the retreat numbers of the Middle Ages a bit. I do believe that book was The 30 Years War