This codex, called the Treaty of Fortification, Statics and Geometry, is made up of two very different parts. The first part of the manuscript contains a whole range of information, veering from the personal to the scientific. The second part is mainly concerned with the casting of a horse intended as a monument to Francesco Sforza, the former Duke of Milan. It was an immense project, which da Vinci was never able to complete. This text is only a partial summary.