Architecture of Scotland in the Roman era which were later replaced by forts. The most visible fortlet is Kinneil, at the eastern end of the Wall, near Bo'ness. Having taken twelve years to build, the wall was overrun and abandoned soon after CE 160. The Romans retreated to the line of Hadrian's Wall. Roman troops penetrated far into the north of modern Scotland several more times, with at least four major campaigns. The Antonine Wall was occupied again for a brief period after 197 CE. The most notable invasion was in 209 when the emperor Septimius Severus led a major campaign. A string of forts was constructed
City Wall and Moat wooden towers. Attackers had to construct bridges from their wooden towers in order to reach the top of the wall, thus exposing themselves to the defenders of the city. Archaeologists have not been able to provide a precise date for the construction of the city wall and its moat, although historical chronicles suggest the 9th century. Both wall and moat were built atop the Phoenician cemetery, and cut across the ruins of the Phoenico-Persian, Hellenistic and Roman residences. In the late 19th century, the city wall and its moat lost their strategic significance. By the early 1900s, the wall had