"you can easily enter or leave at your
pleasure. And have this be made in the massive walls,
as far as possible from known reinforcements."
"So that the provisioned soldiers may be roused day
or night by the castellan as he requires. And for this,
they must sleep in quarters of thin planks beneath
the porticos, which must be straight, and with the
embrasures before these porticos."
This relief model illustrates a mountain castle that was probably already in existence in Leonardo's day. Leonardo made improvements in it, with a view to increasing its resistance to the new, powerful firearms that were introduced in the second half of the 1400s. The ravelin was probably located in defence of an entrance at the base of the castle - the entrance being indicated by the caption, sotterranea "underground passage". The ravelin consists of three towers with very steep scarps that give way to a masonry curtain with a raised way, and a buttress at the centre - the angle being of 125°. The two concentric walls stand in defence of the sturdy tower at the centre, which was probably where the lord of the manor lived.
The model is based on the drawing:
- Codex Atlanticus f. 117 r. (1507-1510)
Milano, Biblioteca Ambrosiana