FOLIO 5 (recto)

Facsimile of a manuscript page containing architectural studies for fortifications with accompanying notes in Leonardo's mirror writing.

Method for a ravelinA triangular fortification or detached outwork located in front of the innerworks of a fortress. for a fortress. Foundation for merlonsThe solid upright parts of a battlement, between the embrasures or openings..

Central architectural plan with letters 'A', 'A', 'N', 'p', 'q' used as labels:

This method is for placing the underside of beam p into the upper side of beam q.

Text to the right of the central diagram:

This is a method for a square tower, as it should stand at the upper level where the merlons are built.

Bottom text block near a triangular diagram:

Catoriginal: "gatto" — a mobile penthouse or protective structure used in siege warfare to shield soldiers as they approached a wall. — foundation for a wall-cat; and this will not be damaged, neither from above, nor from below, nor from the side.

— Method for a ravelin for a fortress
— Foundation for merlons
— This method is for placing the underside of beam p into the upper side of beam q.
— This is a method for a square tower, as it should stand at the upper level where the merlons are built.
— Cat — foundation for a wall-cat; and this will not be damaged, neither from above, nor from below, nor from the side.