the fortress of Vimioso
The Book of Fortresses was made in the early 16th century by Duarte de Armas, esquire of King Manuel I of Portugal. It depicts Portuguese fortresses located near the border with the (then) kingdom of Castile — and the Royal Palace in Sintra.
All the drawings were made from direct observation. The second part of the codex shows plans (blueprints — anachronistic term) of some of the fortresses.
the fortress and town of Alandroal
the plan of the Alandroal fortress
The entire codex is on-line here.