Trajan’s Column was inaugurated on 12 May 113 CE as the centrepiece of the Foro di Traiano, the last and most ambitious of the imperial fora in Rome. The project is traditionally attributed to Apollodorus of Damascus, the Greek architect and engineer who already served Trajan on the bridge across the Danube and on the design of the forum itself. The shaft rises about thirty metres and is built from roughly twenty colossal drums of Carrara marble, each weighing in the order of thirty tons; with pedestal and crowning statue the total height reaches some thirty-five metres. The column was conceived as both a triumphal monument and, eventually, an imperial sepulchre.

Its most celebrated feature is the continuous bas-relief that winds twenty-three times around the shaft, from base to capital, telling the story of Trajan’s two Dacian campaigns of 101–102 and 105–106 CE. Modern counts identify 155 distinct scenes and approximately 2,662 carved figures; the emperor himself appears more than fifty times. The relief is not a battle frieze in the ordinary sense: marches, river crossings, sieges, addresses to the troops, sacrifices and engineering works are given as much weight as combat, making the column an extraordinary document of Roman military practice as much as a propagandistic artwork. The carving widens slightly as it climbs, a calculated optical correction so that the upper scenes remain legible from below.

On 4 December 1587 Pope Sixtus V removed the original bronze statue of Trajan from the summit and replaced it with a bronze figure of Saint Peter, which still crowns the monument today. The pedestal at the base of the column, accessible through a small door, was conceived as an imperial tomb: a golden urn with Trajan’s ashes was placed inside after his death in 117 CE, later joined by the ashes of his wife Plotina. The column survived largely intact through the medieval period precisely because of its Christianisation, while the rest of the Foro di Traiano collapsed into the modern Via dei Fori Imperiali. Today the monument is freely visible from the street, and the surrounding archaeological area is interpreted through the nearby Mercati di Traiano – Museo dei Fori Imperiali.