The arcus Diocletiani (Novus) spanned the via Lata south of the arcus Claudii and directly in front of the modern church of S. Maria in via Lata. It was probably built by Diocletian and Maximian in 301 A.D., and stood until the time of Innocent VIII (1488-1492). The fragments of a relief found near this site and now preserved in the villa Medici, which represent triumphal scenes, probably belonged to this arch.
There were at least four arches erected on the via Lata which belonged to region VII. Just north of the Saepta the via Lata was crossed by the aqua Virgo, and here Claudius built a triumphal arch, the arcus Claudii, in commemoration of his victories in Britian in 51-52 A.D. The arch formed part of the aqueduct, and seems to have been in ruins as early as the eight century. Coins of the period represent an arch commemorating these victories of Claudius, which is surmounted by an equestrian statue and trophies. Portions of the travertine foundations, inscriptions dedicated to other members of the imperial family, the fragments of reliefs representing military scenes have been found at various times.
Pictorial Dictionary notes
Arcus Novus, Piranesi interchanges this with the Arcus Divi Claudii.