Trajan’s column is a historical relief. As such, it is well grounded in the Roman artistic tradition, yet the use of a spiral narrative is new. A similar column, possibly the earliest closest parallel, is the Column of Jupiter, set up at Mainz, which was dedicated to the salus, or health, of the emperor Nero (Kleiner, Roman Sculpture, p. 214-215). The main propagandistic message of the column is the celebration of Trajan as conqueror. Trajan took as his model the emperor Augustus. However, while Augustus emphasised his role as primus inter pares of his senatorial peers, Trajan, on the other hand, wished to be celebrated in his role as victorious leader. Moreover, as Augustus, Trajan presented himself as assisted by the gods. Therefore, while Augustus was assisted on the battlefield of Philippi by Mars Ultor, to whom he later dedicated a shrine and then a temple, located in his Forum, Trajan claimed to be assisted by Jupiter. This mirrors Pliny’s statement in the Panegyric that Trajan had been chosen by Jupiter (1.5; 5.3-4; 8.3; 23.4; 94.3-4). However, while Pliny draws a comparison between Trajan, pater patriae, and Jupiter, the ruler of the Cosmos, emphasising the extraordinary dignity and dread conveyed by the sacrosanctitas of both heavenly god and terrestrial ruler (14.5; 21), the reliefs of the column, although emphasising the primary position of the emperor, do not give vent to a comparison between the emperor and Jupiter. In fact, the column, as well as the whole forum, celebrates only the military achievements of Trajan.

155 scenes are depicted in the reliefs, which illustrate the two wars waged by Trajan that ended in the conquest of Dacia, namely the First and the Second Dacian Wars. The reliefs are not presented in continuous harmonious narration, but as a series of episodes, each detached from the other, framed by elements of architecture or landscape. However, only a quarter of the scenes depicted consist of battles; the majority of the reliefs illustrate the imperial profectio, or ceremonial departure of the emperor for the war, his ceremonial return, celebrated as his adventus, the offering of sacrifices to propitiate the gods, the making of camps, or castra, marches, the crossing of the river, with a small number of course infantry battles, cavalry clashes, and sieges, which are usually carried out by auxiliary soldiers rather than Roman legionaries (Coarelli, The Column of Trajan, p. 28). Gods are present, although seldom depicted. The personification of the river Danube, a bearded god, initiates the whole spiral. Jupiter once assists the Romans in a battle, throwing thunderbolts at the enemy. Nyx, the goddess of Night, helps the Romans during a night battle. The depiction of the winged goddess Victoria, writing the victories of the emperor on a shield, closes the narration of the First Dacian War. Thus, the main protagonist is the emperor. Trajan is depicted as slightly bigger than the other figures, always at the centre of the scene. He is often depicted as giving an adlocutio, the speech that was addressed to the army before a battle, or making sacrifices, or giving suggestions to the members of the general staff. A key feature and one of the main characteristics of the frieze should be noted in the presentation of the Dacians, who are depicted no less heroically than the Romans; Thus, Decebalus, the Dacian leader, is depicted in a pose reminiscent of the Doryphoros of Polycleitus, the main source of inspiration for the Augustus of Prima Porta. Although the Dacians are clearly indicated as barbarians, there is a certain sympathy in their depiction that receives special accent here.

The depiction of the First Dacian War includes sixty-six panels, in which three campaigns are depicted. The first campaign starts with the crossing of the Danube, then the Roman army is depicted on the march; a council and the successive sacrifice are followed by scenes of battles in which Jupiter intervenes. The campaign ends when Trajan receives a Dacian asking for peace, against the background of the flight of Dacian families. The second campaign opens with the depiction of a Dacian attack of a Roman fort. Trajan, then, joins his army on a ship; the main central scene is the depiction of a night battle, where the Romans are assisted by Nyx. The third and last campaign starts with the depiction of the Roman army marching northward towards the capital of Decebalus; sacrifices are made, roads are built, and the last battle of the war is fought in a poignant hand to hand combat. Victoria, writing on a shield the imperial victories, concludes the narration (Kleiner, Roman Sculpture, p. 216-219). Soon, however, the emperor had to fight again, as Decebalus had violated the treaty. The reliefs depicting the Second Dacian War include sixty panels. The campaign starts with the depiction of Trajan leaving an Adriatic city, probably Ancona, in which Trajan’s Arch still stands. Once on the battlefield, the emperor offers sacrifices against the background of the bridge erected by Apollodorus on the Danube. Then, various embassies from all over the oikoumenè join the emperor. The storming of Sarmingetusa is preceded by the emperor’s adlocutio to the army, and is followed by a mass suicide of the Dacians, reminiscent of the fate of the defenders of Masada. The relief ends with the depiction of the capture of Decebalus by Roman cavalrymen, while he also tries to commit suicide (Kleiner, Roman Sculpture, p. 219).

Much scholarly discussion has focused on the legitimacy of these scenes, and whether or not they provide an accurate description of the wars as they took place. Others, such as Ian Richmond, have focused less on the historical detail and rather utilised the reliefs for the insight they provide for military equipment and organisation (“Trajan’s Army on Trajan’s Column,” p. 1-40). Filippo Coarelli has argued that rather than representing exact episodes from the wars, the reliefs “use fixed expressive modules that reoccur systematically, freezing the flow of events within cadenced stereotypes,” simplifying and rationalising the action of the wars so that they can be understood by all (The Column of Trajan, p. 27). The reliefs may have been based, as Diane Kleiner argues, on the Commentarii of Trajan – essentially war reports sent from the field to the Senate in Rome – which were conserved in the Greek and Latin libraries of Trajan’s Forum. In this sense, the spiral column may be interpreted as an illustrated scroll, but without the text. Earlier state reliefs, which did not survive, could also have served as a source of inspiration (Kleiner, Roman Sculpture, p. 215).

The two main virtues that are exalted are Trajan’s bravery, or virtus, and his piety, or pietas, which is emphasized by the number of times the emperor is depicted making sacrifices. Indeed, the gods reciprocate the care of the emperor and yet are seldom depicted themselves. In a total of 2500 figures, only four depict gods, namely, the god, who is the personification of the Danube, Jupiter, Nyx, the goddess of Night, and of course Victoria, the goddess of victory. In fact, the reliefs of the column ought to be seen in the context of the whole forum, in which other statues and reliefs were found, which celebrated Trajan as a successful and victorious military commander. Thus, the military achievements of Trajan were announced at the gate of the forum, shaped as a triumphal arch, and topped by the statue of Trajan drawing a six-horse quadriga. The emperor was crowned by Victoria, the goddess of victory, which also appears on the reliefs of the column. Moreover, in the centre of the forum, was located an equestrian statue of the emperor. Statues of Dacian prisoners decorated the porticoes of the forum as well as the façade of the Basilica Ulpia. Thus, the column is in fact only the summit of a series of sculptural groups, whose sole purpose was to emphasise Trajan’s achievements as military commander (Kleiner, Roman Sculpture, p. 212-214). Yet, the depiction of the emperor on the column also raises questions. While the Great Trajanic Frieze (117-120 CE), as well as the reliefs on the Tropaeum Traiani from Adamklissi depict the emperor in the middle of the battle, riding on a horse, and killing his enemies with a spear, in a pose reminiscent of that of Alexander the Great, as depicted on the well-known mosaic depicting the battle of Issos, it is not the case on the reliefs of Trajan’s column. Indeed Trajan is never depicted in scenes of battles with his own soldiers, but rather appears in direction of the campaign as a strategist and a tactician, “a tranquil and rationalising force in an otherwise chaotic reality” (Coarelli, The Column of Trajan, p. 27). The ‘Romans’ are presented as ‘civilising’ entities, rather than bellicose conquerors; imperial conquest is not presented in a glorified nor warlike fashion in the detail of Trajan’s Column, but rather as the product of superior technical innovation and organisation.