I learned a lot from this book.
I learned about the difference between castles and the later forts, the evolution of gunpowder use in the 1400s, the evolution and then disappearance of armor, the Hundred Year War, throwing down the gauntlet, siege warfare and assault warfare, the use of cavalry, the role of peasants and farmers in warfare, the reasons many tried to avoid being knighted, and why Henry Vlll was a great king.
And lots more about their Civil War. It was a bloody history, over all those years, for no good reasons. I suppose it has been like that everywhere. Power, money, land, glory.