All these books are free to read: either they're distributed with a free license, or they're in the public domain.
keyword: History – 390 free books.
Richard Harding and Agustín Guimerá, editors
Lara Pauline Karpenko and Shalyn Rae Claggett, editors
Giovanni Ciotti and Hang Lin, editors
Pal Kolstø and Helge Blakkisrud