The triumphal Arch of Constantine was erected in AD 315 by the senate and people of Rome in honour of Constantine’s victory in 312 over Maxentius.

After defeating his rival Maxentius at the Battle of the Milvian Bridge Constantine moved his residence to Trier in Germany. He only returned to Rome three years later to celebrate the tenth anniversary of his ascent to power.

He inaugurated the arch that the Senate had erected in his honour on the long processional route followed by generals awarded a triumph: it ran from the Field of Mars through the city to the Temple of Capitoline Jove. With a height of 25.7 m. and a depth of 7.4 m., it is the largest and best preserved of Roman war memorials.

As we learn from theinscription over the main arch, the monument was solemnly dedicated to the emperor by the Senate in memory of that triumph and on the occasion of the decennalia of the Empire, at the beginning of the tenth year of his reign on July 25, 315. The text reads,

IMP(cratori) CAES(ari) FL(avio) CONSTANTINO MAXIMO F(io)F(elici) AUGUSTO S(enatus) P(opulus)Q(ue)R(omanus) QUOD INSTINCTU DIVINITATIS MENTIS MAGNITUDINE CUM EXERCITU SUO TAM DE TYRANNO QUAM DE OMNI EIUS FACTIONE UNO TEMPORE IUSTIS REM PUBLICAM ULTUS ESTARMIS ARCUM TRIUMPHIS INSIGNEM DICAVIT.

Translation: To Emperor Caesar Flavius Constantinus Maximus Pius Felix Augustus, the Senate and the People of Rome dedicated an arch decorated with triumphal representations because, through divine inspiration and great wisdom, with his army and just arms he freed the state from the tyrant (Maxentius) and