The exact origins of the Arch are unclear. It is now generally agreed that it has nothing to do with Nero Claudius Drusus, the conqueror of the Germans. Some versions have the arch being constructed as part of a spur added to the Aqua Marcia by Caracalla in 211-216 AD to take water from that aqueduct to Caracalla's new baths. However, it appears more likely that the arch predated the aqueduct and that the aqueduct (aqua Antoniniana) was conveniently routed over the top of the arch.