Arch of Diocletian (Arcus Novus)

Beneath the church of Santa Maria in Via Lata, on what is now the Via del Corso, lie the foundations of a triumphal arch that no longer exists. The Arcus Novus was probably a marble arch adorned with trophies, spanning the road close to the northeast corner of that same church, dedicated to the emperor Diocletian, and destroyed in 1491 on the orders of Pope Innocent VIII. It is now known almost entirely through fragments scattered across Florence and Rome, and the historical record.

Diocletian came to power in A.D. 284 following decades of military crisis and imperial instability. His solution was the Tetrarchy: a system of shared rule in which power was divided between two senior emperors, the Augusti, and two junior ones, the Caesars. Diocletian ruled the eastern half of the empire from Nicomedia, rarely visiting Rome, and his reign left relatively few monuments in the capital. The Arcus Novus is one of them, and its date is itself contested. The historian T. V. Buttrey, whose 1983 article in Historia examined the numismatic and epigraphic evidence closely, argued that the arch should be dated to the joint triumph of Diocletian and his co-emperor Maximian in A.D. 303–304, rather than to Diocletian’s decennalia of 293. The VOTIS X VOTIS XX inscription, recording vows for ten and twenty years of rule, supports the later date, though the question is not fully settled. As for its name, the New Arch, almost certainly referred to the earlier Arch of Claudius on the same road, though like its date, this remains unconfirmed.

The arch was notable above all for its use of sculptural material taken from earlier monuments, what scholars call spolia. The Arcus Novus was built in part from sculpture stripped from earlier monuments, including relief panels from a Julio-Claudian monument most probably identified as the Ara Pietatis. The column plinths bore figures of Victoria, barbarian prisoners, and the Dioskouri, elements likely taken from the nearby Temple of the Sun built by the emperor Aurelian. In doing so, Diocletian was establishing a practice that would become standard in the fourth century: claiming visual continuity with the Roman past while building quickly. The Arch of Constantine, dedicated in A.D. 315, took the practice further still: some scholars argue that the sculptural frieze it is most famous for was itself stripped from a lost Diocletianic monument, possibly the Arcus Novus itself.

The physical remains of the Arcus Novus tell a dispersed story. Fragments discovered in 1523 entered the Della Valle collection before being acquired by Cardinal Ferdinando de’ Medici in 1584. The column plinths ended up in the Boboli Gardens in Florence; other panels were set into the rear facade of the Villa Medici in Rome, where they remain. Further fragments excavated between 1923 and 1933 are now in the Centrale Montemartini. A monument built to project permanence survives in pieces, spread across two cities.

FURTHER READING

• Buttrey, T. V. “The Dates of the Arches of ‘Diocletian’ and Constantine.” Historia: Zeitschrift Für Alte Geschichte, vol. 32, no. 3, 1983, pp. 375–83. JSTOR, http://www.jstor.org/stable/4435857. Accessed 17 July 2026.
• Kinney, Dale. “‘SPOLIA. DAMNATIO’ AND ‘RENOVATIO MEMORIAE.’” Memoirs of the American Academy in Rome, vol. 42, 1997, pp. 117–48. JSTOR, https://doi.org/10.2307/4238749. Accessed 17 July 2026.
• Richardson, Lawrence. A new topographical dictionary of ancient Rome. JHU Press, 1992.
• Elsner, Jaś. “From the culture of spolia to the cult of relics: the Arch of Constantine and the genesis of late antique forms.” Papers of the British School at Rome 68 (2000): 149-184.