To the Doric, Ionic, and Corinthian orders Rome added the Tuscan and Composite styles, and certain modifications. Columns were often monoliths instead of superimposed drums. The Doric column received an Ionic base and took on a new, unfluted slenderness; the Ionic capital was sometimes given four volutes to offer the same appearance from every side; the Corinthian column and capital were developed to a delicate beauty beyond any Greek example, but in later decades this style was spoiled by undue elaborations. A like excess poured flowers over the Ionic volutes to make the Composite capital, as in the Arch of Titus; sometimes the volutes ended in animal or human forms suggestive of gargoyles and presaging medieval forms. The lavish Romans often mixed several orders in the same building, as in the theater of Marcellus; and then again, with perverse economy, they left the side columns attached to the cella, as in the Maison Carree at Nimes. Even when the development of the arch had taken from columns their old supporting role the Romans added them as functionless ornaments- a custom that has survived into our own uncertain age.
2. The Temples of Rome
For nearly all her temples Rome kept the Greek trabeate principle- architraves (i.e., master beams) upheld by columns and carrying the roof. Augustus was conservative in art as in everything else, and most of the shrines built by his order clung to the orthodox tradition. From his time onward the emperors multiplied homes for their Olympic rivals and clothed their lechery with an architectural piety that crowded the hills and blocked the streets with tiled and gilded fanes. Jupiter, of course, was their favorite recipient. Among many he had one as Jupiter Tonans, the Thunderer; another as Jupiter Stator, who had stayed the flight of the Romans in battle; and he shared with Juno and Minerva the holiest of Rome’s sanctuaries, atop the Capitoline hill. There in the central cell, flanked by a three-storied Corinthian colonnade, was the gold-and-ivory colossus of Jupiter Optimus Maximus- Jove the Best and Greatest. Tradition ascribed the first form of this supreme house of Roman worship to Tarquinius Priscus; it was several times burned down and rebuilt; Stilicho (A.D. 404) stole its gold-plated bronze doors to pay his soldiers, and the Vandals carried off the gold-plated tiles of the roof. Some fragments of the pavement remain.
On the northern summit of the same hill rose the Temple of Juno Moneta, Juno the Monitor or Guardian; here was the Roman mint, and from its name, of course, comes our word for the root of much ambition. On the south side of the hill was the shrine of Saturn, the oldest god of the Capitol; the Romans dated its first dedication at 497 B.C.; eight Ionic columns and an architrave survive. In the Forum, at the foot of the hill, was the little Temple of Janus, god of all beginnings; its doors were opened only in time of war, and were closed but three times in Rome’s ancient history. At the southeast corner of the Forum stood the Temple of Castor and Pollux, erected in 495 B.C.; three slender Corinthian columns have come down to us from the reconstruction by Tiberius; they are by common consent the finest columns in Rome.