Trajan, 25 January 98 - 8 or 9 August 117 A.D.

Marcus Ulpius Traianus, a brilliant general and administrator was adopted and proclaimed emperor by the aging Nerva in 98 A.D. Regarded as one of Rome's greatest emperors, Trajan was responsible for the annexation of Dacia, the invasion of Arabia and an extensive and lavish building program across the empire. Under Trajan, Rome reached its greatest extent. Shortly after the annexation of Mesopotamia and Armenia, Trajan was forced to withdraw from most of the new Arabian provinces. While returning to Rome to direct operations against the new threats, Trajan died at Selinus in Cilicia.Trajan's "bridge reverse" is normally linked with the monumental bridge built across the Danube by the famous architect Apollodorus of Damascus, an amazing example of Roman engineering. But Apollodorus' bridge is believed to have differed greatly from the bridge on coin and some scholars doubt any connection between the two. G.F. Hill suggested the bridge is the Pons Sublicius, a revered ancient wooden structure in Rome, often damaged by floods and presumably restored under Trajan. We could argue that the Danube Bridge is still a possible subject, since architecture is notoriously schematized on ancient coins.

While Apollodorus' own writings on the bridge are lost, it is depicted on Trajan's Column, and discussed in the writing of Cassius' Dio and Procopius of Caesarea, among others. The bridge, constructed with wooden arches set on twenty masonry pillars, is estimated to have been 1135 meters long and the river about 800 meters wide. Each gateway was protected by a castrum. Procopius tells us that during construction the river was diverted and about half of the pillars were built on dry land. Cassius Dio tells us that Hadrian removed the wooden arches to protect Moesia from northern invasions. Since Dacia continued to be a province for about the next 150 years, the bridge must have been rebuilt. Aurelian likely demolished it when he abandoned Dacia. In 1856, when the Danube was at a record low, all twenty pillars were seen out of the water. In 1906 two were demolished to ease navigation. In 1982 archeologists could only find the remains of twelve pillars. Both end pillars are still standing on the Serbian and Romanian shores.