Scotland during the Roman Empire of the geography of Scotland had extended to the "Hebudes" (The Hebrides), "Dumna" (probably the Outer Hebrides), the Caledonian Forest, and the Caledonians. Ptolemy, possibly drawing on earlier sources of information as well as more contemporary accounts from the Agricolan invasion, identified 18 tribes in Scotland in his "Geography", but many of the names are obscure. His information becomes much less reliable in the north and west, suggesting early Roman knowledge of these area was confined to observations from the sea. Famously, his coördinates place most of Scotland north of Hadrian's Wall bent at a right angle, stretching due eastward
Architecture of Scotland in the Roman era in the north-east (some of which may have been begun in the earlier Antonine campaign). These include camps associated with the Elsick Mounth, such as Normandykes, Ythan Wells, Deers Den and Glenmailen. However, only two forts in Scotland, at Cramond and Carpow (in the Tay valley) are definitely known to have been permanently occupied during this incursion. There is evidence that these campaigns are coincident with the wholesale destruction and abandonment of souterrains in southern Scotland. This may have been due either to Roman military aggression or the collapse of local grain markets in the wake of Roman withdrawal. After