Located on the Monument Hill in the North-Eastern section of Tulcea, the fortress was built at the end of the 4th century B.C. Its name, of Celtic origin, derived from a legendary founder, Caspios Aegyssos. Reporting the events of the year 12 A.D., when the town was attacked by the Getae, Ovidius called it the attribute uetus urbs (old town). At the beginning of 2nd century, the town was included in the Danubian limes (boundary). Then, starting with the 3rd century, it became an important military headquarters. The 6th century finds it as an episcopal residence. Urban life knows an end in the first quarter of the 7th century and a revival in the 10th and 11th centuries.
Currently, on the Monument Hill, several archaeological complexes from the late Roman epoch can be visited. Many archaeological materials, discovered during the research organized in the second half of the 20th century, can be found in the permanent exhibition of the Museum of History and Archaeology found nearby.
(*** Reference source: Tulcea County travel guide, Tulcea, 2011)