Emperor Trajan is known for his lasting and praiseworthy building feats. In anticipation of the war against the Dacians, Trajan carved a path in the rocks by the side of the Danube and erected a bridge over this major European river. To enable normal sailing on the Danube, he also dug out the Sip Canal in 101. And to better control the entry and exit of ships to and from the Iron Gate and their sailing through the gorge, he built Diana Fortress on a towering rock above the Danube.

The fortress was built on the site of an old fortification made of earth and wood, at the time of arrival of the first military formations to this area, in the early 1st Century. At the time, the area was bustling with economic and commercial activity. Numerous marble and bronze statues, as well as household items for everyday use, were transported by ships which docked at the port and harbour by the fortress.
To protect this part of the bank, ramparts were added to the original construction in the late 3rd and early 4th Century, descending from the northwest and northeast corners to the Danube, which gave the fortress its final shape.
Diana played an important role in defending the Empire and controlling the sailing route on the Danube all the way to the 5th Century, when it was razed to the ground by the Huns. Around 530 CE, the fortress was rebuilt by Emperor Justinian; unfortunately, its’ “second life” would turn out to be brief. At the time of incursions by Avars and Slavs in the late 6th and early 7th Century, the fortress was destroyed for good. The remains include parts of buildings with an apse, military barracks and other military facilities inside the walls of the fortress. The central part of the fortress includes the remains of the principium with a portico, while the remains of a shrine, martyriums and part of a necropolis are found outside the walls.
To round off your visit to Diana, take a tour of the remains of the ancient city of Ziana, situated to the west of the fortress, towards the Danube.