The “Livro das fortalezas situadas no extremo de Portugal e Castela por Duarte de Armas, escudeiro da casa do rei D. Manuel I” is an analysis, dating back to early 16th Century, of the Portuguese fortresses located near the border with the Kingdom of Castile and of the Royal Palace in Sintra.

Duarte de Armas, esquire of Manuel I of Portugal, filled this codex with drawings in plan and pseudo-perspective, depicting the fortresses from direct observation.

A complete version is available online here.

Via: Da Palaeographia