The orders thus changed were employed for the most part as mere decorative additions to the walls. In many cases they did not even carry the eaves of the roof, as they always did in a Greek temple; and it was not uncommon for two, three, or more orders to be used one above another, marking the different stories of a lofty building.
The columns, or pilasters which took their place, being reduced to the humble function of ornaments added to the wall of a building, it became very usual to combine them with arched openings, and to put an arch in the interspace between two columns, or, in other words, to add a column to the pier between two arches (Fig. [146]). These arched openings being often wide, a good deal of disproportion between the height of the columns and their distance apart was liable to occur; and, partly to correct this, the column was often mounted upon a pedestal, to which the name of “stylobate” has been given.
It was also sometimes customary to place above the order, or the highest order where more than one was employed, what was termed an attic—a low story ornamented with piers or pilasters. The exterior of the Colosseum (Fig. [5]), the triumphal arches of Constantine (Fig. [139]) and Titus, and the fragments of the upper part [!-- original location of Fig. 146 --] of the Forum of Nerva (Fig. [147]) may be consulted as illustrations of the combination of an order and an arched opening, and of the use of pedestals and attics.
Fig. 146.—Part of the Theatre of Marcellus, Rome. Showing the combination of Columns and Arched Openings.
Fig. 147.—From the Ruins of the Forum of Nerva, Rome. Showing the use of an Attic Story. With Plan.
Another peculiarity, of which we give an illustration from the baths of Diocletian (Fig. [148]), was the surmounting a column or pilaster with a square pillar of stone, moulded in the same way as an entablature, i.e. with the regular division into architrave, frieze, and cornice. This was a decided perversion of the use of the order; it occurs in examples of late date. So also do various other arrangements for making an arch spring from the capital of a column; one of these, from the palace of Diocletian at Spalatro, we are able to illustrate (Fig. [149]).