ENGAGED COLUMN, in archi tecture, a structure taking the form of a column partly embedded in a pier or wall, a half or three-quarter column attached to a pier or wall face. Engaged columns are usually built integrally with the wall of the building of which they form a part, but occasionally, due t o the use of the lathe, they are made of separate stones, and in woodwork are almost always separate pieces glued or nailed in place. Engaged col umns occur rarely in Greek work, as in the temple of Zeus at Agrigentum (c. 5oo B.c.) ; they are, however, common in Roman buildings. As a wall decoration they are occasionally used in temple walls where colonnades are only at the front, as in the temple of Fortuna Virilis, in Rome (c. 15o B.c.), and the Maison Carre at Nimes (time of Tiberius). Their most common use is to decorate the piers of arcades, as in the Colosseum at Rome (A.D. 8o), and this combination of arch and engaged column is sometimes termed the Roman order. In mediaeval architecture, engaged columns frequently form the component parts of clus tered piers. They are common in all Renaissance styles.