The Trajan's Column was erected in the year 113 to celebrate the conquest of Dacia by Emperor Trajan. This is the first spiral column ever made, decorated with a long frieze that wraps from the bottom up all over the shaft of the column, describing the wars of Dacia (101-106). At the top stood a bronze statue of Trajan. It was placed in the Forum of Trajan, in a courtyard behind the Basilica Ulpia. A quick reading of the column is possible even without turning around the shaft of the column to follow the whole story, but following the scenes in a vertical order, since their overlap in different loops follows a consistent logic. The column remained standing even after the downfall of the other buildings in the complex, and always had a great importance: a document from the medieval Senate dated year 1162 established the public property and prohibited any damage to it. Under Pope Sixtus V in 1588, a bronze statue of St. Peter was placed on top of the shaft. The column is 100 Roman feet high (equal to 29.78 meters, 40.50 meters including the pedestal and the statue at the top), and consists of 19 colossal marble blocks, each of which weighs 40 tons and a diameter of 3.83 meters. At the base there is the door that leads to the interior of the basement, where the ashes of Trajan were located, and where begins a spiral staircase of 185 steps leading to the summit. The 200 meter frieze rolled up in a spiral around the stem for 23 times, and bear around 100-150 scenes, with approx. 2500 figures. The height of the frieze increases with height, from 0.90 to 1.25 meters, in order to correct the perspective distortion upward. The construction of the monument required a complex and advanced technical organization and coordination between the workers, that had to overlap blocks of marble weighing about 40 tons and fit them perfectly, taking into account both the frieze, probably already sketched, and the spiral staircase, which had already been dug in the blocks prior to placement. The high quality of the survey did give the sculptures to an unknown "Master of Business of Trajan", which perhaps is also responsible for the so-called "Great frieze of Trajan" whose plates are reused on the Arch of Constantine. The column served as a model to Trajan Column of Marcus Aurelius, in Rome, built about eighty years later (180-193). Then followed many other in Constantinople at the time of Theodosius I, Arcadius and Justinian I, and others more recent, at the time of Napoleon I (the Vendome Column).