Situated on the triumphal route that led to the Capitoline Hill, the Arch of Severus was erected by the Senate in AD 203 on the tenth anniversary (decennalia) of the emperor's accession and in commemoration of his defeat of the Parthians and the capture of Ctesiphon in AD 198. Originally, the arch was surmounted with a statue of Severus and his sons riding in a chariot drawn by six horses. In AD 212, after Caracalla became emperor, he murdered his brother Geta and removed his name from the dedicatory inscription.
The Arch of Severus was the first major architectural addition to the Forum in eighty years. Placed diagonally opposite the Arch of Augustus, which also had been erected to celebrate a triumph over the Parthians, it symbolically linked Severus, who had come to power after a bloody civil war, with Rome's first emperor. So debilitating was this struggle, as Roman legion fought Roman legion, that Gibbon considered Severus to be the principal author of the decline of the Roman empire.
