The structural relationships of the forts, Wall curtain and Vallum are reviewed and a revised sequence of construction for Hadrian's Wall is proposed. The original plan (Stage 1) incorporated much of the earlier Trajanic frontier (the Stanegate) and probably included the Devil's Causeway which ran north-eastwards from Corbridge. Forts were then added to the line of the Wall as a result of three modifications of the plan (Stages 2–4), continuing until late in Hadrian's reign. The Vallum was added in Stage 3. Hadrian probably conceived the original plan for the Wall, but the modifications that followed seem to have been consequences of shifting focuses of loyalty, resistance and outright warfare, beyond and behind the frontier.