General Rules of Architecture

In this gateway, the ingenious Architect may make use [of this design] in various places, as was stated at the beginning; however, not for fortress gates, because the entrance or vestibuleoriginal: "vestibolo"; a foyer or hallway leading from the door into the interior (as we might call it) would not be suitable for handling artilleryoriginal: "artigliarie"; large cannons or heavy mounted weaponry or large weapons for defense. Nevertheless, the exterior portion can serve for any doorway. Its proportions shall be such that the height of the opening is twice its width. The wedgesoriginal: "cunei"; also known as voussoirs, these are the tapered stones that form the arch and distribute weight of the semi-circle shall be nine in number, and let all their lines be drawn toward the center of the circle. The flat bandoriginal: "fascia piana"; here referring to the impost, the block upon which the arch rests that supports the arch should be one-seventh the width of the doorway. From this band down to the floor, the space shall be divided into seven and a half parts, and six courses of stones shall be made: three of these shall be one and a half parts each, and the other three shall be one part each, and in this way the seven and a half parts shall be distributed. The height of the middle wedgeoriginal: "cuneo di mezo"; the keystone, which locks the arch together at its highest point should be half the width of the doorway. The moldingoriginal: "fascia"; a decorative strip or band running along the outer edge of the arch that runs above the wedges should be as high as the "foot" (the inner edge) of the wedges; however, the middle wedge shall be one-fourth larger than the others.

Illustration of a rusticated stone portal or gateway featuring heavy, textured ashlar masonry. The central opening is a semi-circular arch composed of nine prominent wedge-shaped stones, with the central keystone being larger than the others. Through the archway, a short vaulted vestibule is visible, leading to another arched opening in the background. The masonry courses on the facade vary in height according to the proportions described in the text.