In the midst of the busy quarters lying at the base of the Quirinal, you come out upon a great piazza which you name at once without ever having seen it before; Trajan’s Column serves as ensign for a forum, of which Apollodorus of Damascus erected the porticoes. The lines described by the bases of a plantation of pillars will help you to identify the pesimeter of the temple which Hadrian consecrated, and the site of the Ulpian Library which was divided into two chambersone for Greek books, and the other for Latin; and finally the situation of the basilica, opening on to the forum and with its apse in the north-northwest direction.
It was in the Ulpian Basilica that, in 312, Constantine, having assembled the notables of the empire seated himself in the presbyterium, to proclaim his abjuration of polytheism in favor of the religion of Christ; on that day and spot the prince closed the cycle of antiquity, opened the catacombs, and inaugurated the modern world. The Acts of St. Sylvester describe many passages of the discourse in which, “invoking truth against mischievous divisions,” and declaring that he “put away superstitions born of ignorance and reared on unreason,” the emperor ordains that “churches be opened to Christians, and that the priests of the temples and those of Christ enjoy the same privileges.” He himself undertakes to build a church in his Lateran palace.
I do not think there exists any monument in the world more precious or more exquisite in its proportions than Trojan’s Column, nor one that has rendered more capital service. This has been set forth with more authority than I can pre-tend to, by Viollet-le-Duc, the architect who has written best on his own art; his description sums up the subject and makes everything clear. A set of pictures of the campaigns of Trajan against the Deciansthe bas-reliefsreproduces the arms, the accouterments, the engines of war, the dwellings of the barbarians; we discern the breed of the warriors and their horses; we look upon the ships of the time, canoes and quinqueremes; women of all ranks, priests of all theogonies, sieges, and assaults. Such are the merits of this sculptured host, that Polidoro da Caravaggio, Giulio Romano, Michael Angelo, and all the artists of the Renaissance have drawn thence models of style and picturesque grouping.
Trajan’s Column is of pure Carrara marble. The shaft measures about ninety-four English feet, by twelve in diameter at the base, and ten below the capital, which is Doric and carved out of a single block; the column is composed of thirty-four blocks, hollowed out internally and cut into a winding stair. A series of bas-reliefs, divided from one another by a narrow band, run spirally around the shaft parallel to the inner stair-ease of a hundred and eighty-two steps, and de-scribes twenty-three circuits to reach the plat-form on which the statue is placed. The foot and the pedestal are seventeen feet high; the torus, of enormous diameter, is a monolith; the whole construction rises a hundred and thirty-five feet from the ground. These thirty-four blocks, measuring eleven meters in circumference by one in height, hada task of considerable precisionto have holes drilled in them for the screws of the stair-ease, it being necessary to determine from the in-side precisely where these borings must be made in order not to break the continuity of the bas-reliefs, executed by several different hands, and which are more deeply worked in proportion as they gain in height, so as to appear of an equal projection.