How Did You Decide to Write a Book?

Partly historical and partly just personal, psychological. The last mediaeval book of dit was about the crusades. But i had this sort of feeling i wanted to do something that wasn't just military or religious or political. And i wanted to just see how big i could go. So a big history of themiddle ages felt like something when there was low o places to go historically,. That would be a challenge. Narratively, that woull keep me sort of focused and interested. And then speaking personally and psychologically. I've just turned forty, and it was my tenth book. It's hard to go bigger.