The Basilica Ulpia, which derives its name from Trajan’s family name and served as a court of justice, lay at a right angle to the end of the square. In the current state of development it is difficult to grasp the size of this hall, which measured 130 x 125m/427ft x 410ft (largest basilica ever built in Rome), and even in Trajan’s time it was not easy to fit a building of these dimensions into the centre of Rome.
Fact: Four panels in Arch of Constantine from the reign of Trajan were taken from the attic of the Basilica Ulpia.
Two libraries, one for Latin and one for Greek literature (designed by Apollodorus), lay next to the basilica; the victory column for Trajan towered between them. The complex, which was greatly admired in ancient times and of which only the triumphal column remains today, honoured the emperor under whom the Roman Empire reached its greatest extent.