In this volume we get the spread of knowledge and religion via the Silk Roads, and a blatzkreig of fighting in China.
We also see the growth of Byzantium out of the Eastern Roman Empire, and the birth of Islam, which starts out okay. But after the death of Mohammed, his Arab followers, just like the Christians at the time, almost immediately split into factions. It’s not about doctrine, it’s just a power play among families. And this split between the Sunni and the Shia, with the explosive emotional power of religion behind it, has remained fresh and messed up to this very day. Like what England went through with the Catholics and the Protestants. Ugh.