Of the famous triumphal arches left by Roman builders, the majority employed the use of the Order in either the Corinthian or Composite forms. These arches were generally of two types. In one-the grander and the more imposing-there was one large central arch for the passage of horses and chariots, with two small arches for foot passengers, one on either side. Of this type, the Arch of Constantine,. built 312 A. D. (Fig. 136), is perhaps the best example. It is decorated with separated or detached columns of the Corinthian Order, and is crowned, as was usual in this form of monument, with a heavy Attic story. It must be remembered that these structures customarily carried an elaborate sculptured quadriga of horses and statues, which would do much to break the sky-line and add to the festal effect of the composition.

The other type was of a single arch supported by rather heavy piers, either plain or ornamented. Of this type, perhaps the best example is the Arch of Ancona, dating from about 112 A. D. (Fig. 137), which, being placed at the head of a flight of steps whereby alone it can be approached, is somewhat unique.

Other Roman arches were built in various colonies of the Empire. In many cases they formed the entrance gates to a town or a fortified camp, though frequently they were placed at the intersection of two principal streets, which were probably colonnaded along some part of their length.

Fig. 136. Arch of Constantino, Rome.

Fig. 136. Arch of Constantino, Rome.

Fig. 137. Arch of Trajan, Ancona.

Fig. 137. Arch of Trajan, Ancona.

Of these long colonnaded streets there are many remains. Probably the most imposing are those at Palmyra, where the enormous size of the columns and the remaining evidences of the great length of these streets make the ruins, even to-day, tremendously impressive.

The great simplicity and good proportions of the Arch of Titus make it the most successful of any of these structures. The columns are attached (those on the Arch of Constantine being separated); and the simplicity of the whole design, with the concentration of interest at the same time upon the carved panels that contrast with the otherwise plain surface of the stone, makes it especially commendable from a modern point of view.

There are two other Roman arches employing the use of this Order that may be specially mentioned-one of the single-arch and one of the triple-arch type. The first of these in point of date is the Arch of Beneventum, 114 A. D., erected in honor of Trajan, which is a most elaborately carved and ornamented example of the single arch, entirely lacking the good proportions of the Arch of Titus.

The Arch of Septimus Severus, 203 A. D., is an example of the triple gateway with detached Composite columns, carrying less architectural carving than the one already mentioned.