The triumphal arch
A wall pierced by one or three arches, framed by columns on pedestals and crowned by an attic: the Arch of Titus (c. AD 81) and the Arch of Constantine (AD 315).
The rules it illustrates
The triumphal arch. Pierce a massive rectangular pier with one arch, or with a tall central arch between two lower ones; frame the openings with columns on pedestals carrying an entablature, and crown the whole with a high attic for the dedicatory inscription.
Where it appears in the book
In the styles Ancient Roman.
In the chapters The Composite Order, The Classical World.