After the conquest of the Dacia, which took place in 107 after Christ the Traiano Forum, born to celebrate the grandness of the imperator, was inaugurated only 5 years later, together with the Basilica Ulpia and only a year before the Traiana Column.

The complex of the forum, more complicated in the planimetry respecting the previous ones, is developed on a rectangular area 300 metres long and 180 metres large.
The big dimensions of the monuments and of the various buildings do not leave any doubt on the role of auto celebration of the Traiano Forum, it is enough, for example, to think about the area of the central square which was a rectangle of 120 metres on 60 metres, or to think that the Basilica Ulpia was covering a space of 120 metres on 90 metres, or that the highness of the Traiana Column reaches almost 40 metres.
The access to the main square was done through an arch open along the convex perimeter wall, at the centre was placed the equestrian statue of the imperator Traiano, while all around were placed arcades, on the same style of what had been done for the forum of August. The back of the square was reserved to the Basilica Ulpia, decorated, such as the rest of the colonnade, with statues of the Daci and subdivided in 5 spacious naves; at its shoulders, in a small area extracted between the façades of the two libraries, was arising the Traiana Column. In the Forum of Traiano were taking place the most important public celebrations, such as the one of 118 after Christ in which the Imperator Adriano destroyed all the write-up of the debts contracted by the citizens with the revenue, but the entire decorated complex, from the relieves of the Traiana Column to the ones of the cherubs and of the griffons on the entrance walls, had the assignment to demonstrate not only the magnificence and the great extension of the empire of Rome but also the peace and the stability reached in the confrontations of all the neighbouring populations.