Except for the interest aroused by their cemeteries, the extramural territories of the Roman cities of Britain have never aroused sufficient interest for them to have been subjected to systematic exploration. Nevertheless, as a sensitive barometer to chart their changing fortunes, the margins of a city have considerable potential, as Esmonde Cleary's review of the evidence from the cities and towns of Roman Britain amply demonstrated. Much of what we know derives from the results of adventitious rescue excavation carried out in the context of inter- and post-War city and town development, but comparatively little has emerged from greenfield sites like Calleva which have very largely escaped modern interference. Since the final season of the Society of Antiquaries’ excavation of Silchester in 1909 when attention focused on the ditches surrounding the town wall, only limited investigations have been made of the extramural territory of Calleva. Both Cotton and Boon excavated parts of the Outer Earthwork on the western side, but the evaluation of the defensive sequence was their principal objective, rather than an understanding of the extramural terrritory per se. That has had to wait for the systematic study of the aerial photography and material collected by field-walking which has given us a first glimpse of the organization and use of the extramural territory, and which has now been complemented by the publication of all the aerial photography from Silchester. The two types of survey have shown that the main axis of extramural activity is east-west along the roads leading to London and Cirencester/Bath. However, there is almost no aerial photography to illuminate our understanding of the north-south routes to Dorchester-on-Thames and Chichester/Winchester, although surface collection has revealed spreads of material extending over three hundred metres south of the South Gate through to trie fourth century.6 To the north, however, extensive semi-permanent pasture has hindered non-intrusive investigation and only the evidence of major structures such as the road to Dorchester, and elements of lanes and streets, have been evident from the aerial photography.