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
Architecture of Scotland Trimontium, and a continuous fortification between the Firth of Forth and the Firth of Clyde known as the Antonine Wall, built in the second century AD. Beyond Roman influence, there is evidence of wheelhouses and underground souterrains. After the departure of the Romans there were a series of nucleated hill forts, often utilising major geographical features, as at Dunadd and Dunbarton. Castles arrived in Scotland with the introduction of feudalism in the twelfth century. Initially these were wooden motte-and-bailey constructions, but many were replaced by stone castles with a high curtain wall. In the late Middle Ages new castles were