Roman Britain rising in the north which was suppressed by Quintus Pompeius Falco. When Hadrian reached Britannia on his famous tour of the Roman provinces around 120, he directed an extensive defensive wall, known to posterity as Hadrian's Wall, to be built close to the line of the Stanegate frontier. Hadrian appointed Aulus Platorius Nepos as governor to undertake this work who brought the ' legion with him from '. This replaced the famous "", whose disappearance has been much discussed. Archaeology indicates considerable political instability in Scotland during the first half of the 2nd century, and the shifting frontier at this
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