I see your logic, but everything becomes a lot more complicated the more we change it. That's the main reason I wanted to stick with "as close to real life as possible" because the more we change the threads the more work it is to create an entire technological history. I can't just change some, because it leads to too many questions about how things worked. And the truth is, I wouldn't mind doing all of that, over time, and building a database complete with a timeline. But I don't want to do it alone.

In my timeline prior to this conversation, the war didn't hurt technology too much. Magic was a factor, but it was not powerful enough to wipe out all knowledge of stuff. It was much less WWII and more a 15th century war, fought on moving battlefields, with horses, infantry, and not much more advanced than a crossbow, at least on the human side, which largely didn't know magic at the time.

Due to controlling the slaves, and the mere existence of magic as something to study, mind control tech, imprisonment tech, and magical technology are all more advanced than they were in our world. But otherwise, things are roughly the same, technologically. This whole line of questioning started for me because the presence of magical slaves would change the social and cultural dynamic, first in relation to the history of slavery, but also in some other social and cultural aspects as well.

Now we don't have to keep that, but the more we reconstruct, the more work it is, because every field affects every other field in the longterm, to say nothing of social and cultural changes from different avenues of technological advancement.

To answer the more pressing question, I would say the war lasted around 60 years? That could add some justification to the sins of Joseph's early life as well.