The first part of this thesis is concerned with the assimilation of Pisidia into the Roman Empire, reviewed against a background of general expansion and development. Hellenistic and Roman influences contributed to the transformation of a district with a basically tribally-structured society, primitive communications and a self-sufficient agrarian economy, into a Roman province which had adopted Roman culture and urbanisation, whose road network was part of an Empire-wide system and whose economy was integrated with that of the Empire as a whole. Still it appears that, for fundamentally geographical reasons, Pisidia retained some of her independent characteristics and the process of assimilation of the highlands into the Empire was, on the whole, more retarded than that of the lowland and coastal regions. The second part of the thesis is concerned with aspects of later Antiquity, beginning with the archaeological evidence for Christianity in Pisidia. This is of major importance because Christianity was one of the critical and most influential aspects of change in the Roman world and because the churches are very often the only evidence which bears witness to the occupation of a site after the 4th century. There is thought to have been an Empire-wide decline during late Antiquity, resulting in urban decay, economic dislocation, depopulation and discontinuity of city life and traditions. The main cause seems to have been political instability, in particular almost continual warfare from the mid 3rd century. These and other possible factors of decline are assessed against a background of general transformation and development, the symptoms reinterpreted, whenever justifiable, as reflections of changing traditions and changing needs. The closing chapter considers more specifically the questions of continuity, decline and change in Pisidia, exploring the possibility that Pisidia's element of independence and her geographical isolation protected the district to a certain extent from adversities which were not the result of natural causes.