Giovanni Battista Calvi

[1] He later worked in Siena, at the time also under Spanish sovereignty, with Diego Hurtado de Mendoza as governor of the garrison.

[2] In 1552, he was sought out by Philip II (then only a Prince) to fortify the Spanish coasts and the frontier with France in the Roussillon.

[3] Calvi was the first engineer to provide comprehensive reports on the status of the defensive projects of Spain and the Spanish North-African possessions.

[6] During his inspection trips, he visited Mers El Kébir, Oran, Melilla, Valencia, Burgos, Medina del Campo, Valladolid or Granada.

It has been said that his work "is the basis of all what was subsequently accomplished in the fortifications of the Peninsular kingdoms"[7] and that he was "one of the best engineers of the 16th century, the first to devise a global plan for the defense of the [Iberian] Peninsula".