The Forum of Trajan, unlike that of Nerva, is better known in literature than in art. Its magnificence, surpassing that of any other group of buildings in imperial Rome, furnished material for enthusiastic descriptions in ancient times, but so much of it has been ruined and buried for centuries that only one of its great hemicycles, with the column itself, has been available to artists through the centuries.
Trajan built this last and largest of the forums of ancient Rome early in the second century A.D., partly to give more room for the increasing needs of a growing population, but mainly to carry through the plan of his predecessors of opening southern Rome to the Campus Martius by cutting through a thin ridge between the Capitol and Quirinal hills. Lying northwest of the Roman Forum, its main entrance was through a magnificent arch at the end next the Forum of Augustus. In the court inside stood a gilded equestrian statue of Trajan. Two sides of this court were closed by immense semi-circular exedrae; one, built on level ground to the south, disappeared long ago, but that on the northeast, built into the Quirinal hill, has in great part survived. Beyond this entrance court lay the colonnaded Basilica Ulpia, called after the emperor, whose full name was Marcus Ulpius Nerva Traianus. Beyond the basilica another court was flanked by two libraries, one for Greek and one for Latin works; between these libraries rose, and rises still, the famous Column of Trajan. The architect who planned this magnificent group was Apollodorus of Damascus, who probably built Trajan's baths as well.
In ancient times this forum saw many memorable events. Here slaves were freed; here the Emperor Hadrian burned the notes of debtors to the state; here Marcus Aurelius sold at auction the treasures of the imperial household to defray the costs of war instead of levying more taxes on his subjects; and here the Emperor Aurelian imitated Hadrian's generosity by burning the lists of political offenders. A little sanctuary to Liberty, marked on the Marble Plan, seems once to have stood in the northern hemicycle, receiving its name, perhaps, from being the place where slaves were freed.
In the markets which surrounded the great exedrae of the entrance court all kinds of wares were sold--vegetables, fruit, flowers, fish, and spices. The fish shops were supplied with running water; the spice shops gave the name of their most important commodity, pepper (pipera), to the medieval street, the Via Biberatica, which ran above the northern exedra.
Trajan's forum was one of the wonders of the Roman world. When the Emperor Constantius II visited Rome for the first time in A.D. 356, he marvelled at the many buildings which outshone those of his own capital at Constantinople. 'But when he came to the Forum of Trajan,' wrote the historian Ammianus Marcellinus, 'a construction unique under the heavens, as we believe, and admirable even in the unanimous opinion of the gods, he stood fast in amazement, turning his attention to the gigantic complex about him, beggaring description and never again to be imitated by mortal men. Therefore abandoning all hope of attempting anything like it, he said that he would and could copy Trajan's steed alone, which stands in the centre of the vestibule, carrying the emperor himself. To this prince Ormisda, who was standing near him, . . . replied with native wit: "First, Sire," said he, "command a like stable to be built, if you can."'
The forum evidently escaped without too much damage from the plunderings of Rome in 410 and 455, for early in the sixth century, Cassiodorus wrote: 'However often one sees the Forum of Trajan it always seems a miracle.' Venantius Fortunatus, Bishop of Poitiers, a contemporary of Pope Gregory the Great in the late sixth century, implied that even then the works of Vergil and of living poets were being read aloud in the halls of the forum's libraries.
As early as the eighth century a typically medieval legend began to link the name of this great Gregory with those of Trajan and his forum, which seems not to have been entirely in ruin then. According to this legend, Gregory, walking one day in the forum and marvelling at its greatness, was struck by a relief which showed Trajan dismounting from his horse to grant justice to a poor widow. He wept at the thought of a man capable at once of such magnificent buildings and such compassion being condemned to perdition as a pagan. Upon his return to Saint Peter's he heard a voice from heaven which told him that his prayers for the emperor's salvation had been heeded, but counselled him never again to intercede for unbelievers.
In the course of centuries, medieval and modern buildings enclosed the remaining exedra so that it could not be seen from the street. The French excavated the paving in front of it in 1812, but little was done to make the hemicycle easily visible. As late as 1925 Muirhead's Blue Guide says of it: 'The remains of one of the great exedrae may be seen at No. 6 Via Campo Carleo, or by passing, with permission, through the bakery at No. 33 Via Alessandrina. One of the smaller semi-circular flanking recesses is now occupied by the Ristorante della Basilica Ulpiana.' This restaurant was in a small exedra opening to the left of the hemicycle.
Extensive excavations begun in 1928 have revealed a labyrinth of halls and shops and storerooms, including a two-story market hall found within the barracks of the Milizie, which lay above the ruins in the direction of the Milizie tower. These, with considerable restoration, are open now as a public monument, somewhat bare and lifeless by comparison with their former picturesque neglect. Though many houses were demolished and whole streets eliminated, other streets still cut across great sections of the forum, while the churches of Santa Maria di Loreto and of the Holy Name of Mary lie above the precinct of the ruined temple which Hadrian built in honour of Trajan at the end of the forum beyond the libraries.
Though most of Trajan's forum lay ruined or hidden for centuries, his column, with its spiral bands of relief, has remained a prominent landmark ever since the emperor raised it. The reliefs, showing scenes from Trajan's conquests in Dacia and providing a magnificent record of a Roman army of the second century, were carved after the immense drums were put in place, and done so skilfully that the joinings are almost concealed. In ancient times they could be studied much better than now, for the libraries which flanked the column had two-storied porticoes which brought spectators more nearly to the proper height.
The Middle Ages treated the column with great care. In 1162, during the revival of interest in antiquity which accompanied the republican revolution and produced the Mirabilia, the Roman Senate passed a resolution to preserve it 'to the honour of the whole Roman people', providing the death penalty for damage. This care was probably not unconnected with the fact that profitable fees were collected from pilgrims who climbed it for the view from its top. The Mirabilia's description gives precisely such details as would appeal to tourists, especially the number of steps their weary feet had climbed: 'The winding pillar of Trajan hath in height one hundred thirty and eight feet, steps in number one hundred fourscore and five, windows forty and five.' Actually, the height, including the base, is about one hundred and twenty-five feet, by modern computation. The number of steps is correct, but only forty-three windows are now listed.
Trajan himself did not design the column as his sepulchre, but the Senate, after his death, decreed that his ashes should rest within it, probably in an urn in the base. Originally the column was crowned by a statue of Trajan, which perished long ago; the statue of Saint Peter which now stands there was erected in 1588. Upon the column which Marcus Aurelius built in imitation of Trajan's there now stands the figure of Saint Paul.