Chronologically the last of the Imperial fora in Rome. The forum was constructed by the architect Apollodorus of Damascus, who worked for Trajan first as a military engineer. The forum, built in AD 107-113 and famous in antiquity for its magnificence, built with the spoils of the Dacian Wars, was a boldly conceived project that involved the removal of part of the Quirinal Hill. The main entrance was marked by a triumphal arch erected in AD 117 soon after Trajan's death. A high colonnaded retaining wall enclosed the forum proper (89 x 118 m exclusive of exedrae). The forum contained the Basilica Ulpia, libraries, a temple and Trajan's Column.