Towards the end of the third century B.C. the Ionic style was generally introduced; yet, according to the nature of Roman architecture, which did but borrow external features from foreign nations, itself supplying the general disposition and constructive forms, it became nothing more than a decorative adjunct: the Grecian style became a Roman order. Attic Ionic influences were naturally more prevalent than those of Asia Minor. This was particularly fortunate, because a canon of mathematical rules early took the place of independent development, hardening the forms into formulas. This mechanical method of design was favored by the extended application of engaged columns and pilasters which did not require the complete execution of the elaborate capital, while, in the decoration of colossal buildings of several stories, the distance from the eye rendered a simplification of the Ionic helices natural, as well as more suitable to the coarse and porous stone employed by the Roman builders. (Fig. 271.) The complicated corner capital of the Ionic style could not, however, be avoided upon the free-standing columns of the temple fronts, and the execution of this member must have been exceedingly troublesome to artisans accustomed to work everything after one model. It is therefore to be regarded as a direct consequence of the Roman architectural system that a variety of the Ionic capitals appeared in later times which omitted the rolls and displayed the spirals upon all four sides. This form, as exemplified by the Temple of Saturn upon the Clivus Capitolinus, seems to have arisen by repeating the two outer sides of the corner capital upon those remaining. The entablature was of great simplicity, perhaps because the comparatively rare employment of this order left it undeveloped.
Before the Roman had decided upon the practical but inartistic repetition of the volutes upon all four sides—by which the nature of the Ionic capital was destroyed, and the spiral treated in the early Asiatic manner as mere ornament—the Corinthian capital had come into general and popular use. It has already been explained, in the section upon Hellenic architecture, that the Corinthian capital attained no typical form in its native country, and could not be ranked with the Doric and Ionic styles, being a mere variety of the Ionic capital without any individual formation of the shaft and entablature. The Corinthian columns of the uncompleted Temple of the Olympian Zeus at Athens, which Sulla transported to Rome about the year 84 B.C. for the rebuilding of the Temple of Jupiter Capitolinus, were, if not the first in Rome, at least those which were in later times taken by Roman architects as typical examples of their style. The Roman architect justly preferred the Corinthian capital because of its capacity for more varied application, without that fatal difficulty at the corners inherent in the Ionic style, and because of its rich effect, even when less carefully and delicately detailed. The preference for the Corinthian may be justifiable, but that form of Composite capital into which it developed, by a multiplication of its ornaments and the addition of four spirals upon the corners, must be regarded as a debasement. (Fig. 273.) The fact should not be overlooked that this arrangement of acanthus around a concave kernel best solves the problem of the capital as a mediating member between the vertical support and the horizontal entablature, as well as between the circular plan of the shaft and the rectangle of the epistyle. (Fig. 272.)
The leaves and tendrils of the capital were at last introduced into the entablature, which thereby assumed a peculiar character, and permitted the Romans, for whom the forms of Hellenic architecture were nothing more than a decorative mask, to place the Corinthian, as an independent order, by the side of the Ionic and the Tuscan or Doric. As the Corinthian base had been formed by a combination of the Ionic and Attic mouldings, the consoles of the cornice resulted from a fusion of Ionic dentils and Doric mutules. The simplicity and slight projection of the dentils did not suffice for the requirements of florid Roman architecture; the horizontal mutules without guttæ, characteristic of the later Tuscan style, consequently took their place, supported by the spiral brackets which had been already employed as the parotides beneath the cornices over Ionic doorways. A richly foliated ornamentation fully harmonized these new members with the acanthus capital, and gave to the entire cornice an independent importance and a certain lavish elegance, soon, however, debased by the extravagance of the decorators. Continued increase of ornament resulted in a want of attention to the general composition—a loss which the multiplication of the details could ill supply, especially as they were without even formal beauty.
