The purpose of this book is to analyse the process of Christianization in western Baetica, part of the southern-most province of Roman Hispania. At present it corresponds with the western zone of Andalusia and the south of the region of Extremadura. The common history of this territory within the Roman Empire provides the context for a comparative study of six different episcopal sites: Córdoba (Corduba); Cabra (Egabrum) in today’s province of Córdoba; Écija (Astigi) in today's province of Seville; Seville itself (Hispalis); Italica (adjacent to modern-day Santiponce), also in the province of Seville; and Niebla (Ilipla) in today's province of Huelva. The lack of historical sources of this period in Baetica forces us to work, almost exclusively, with data from archaeology, epigraphy, and numismatics.

Christianization has often been studied as a process of predominantly religious change. This is the traditional approach taken by ‘Christian archaeology’, the focus of which is on the expansion of the new religion and its liturgical modifications. However, this book analyses the process of Christianization in a very different way, from the point of view of social history. The central argument is that an exhaustive analysis of the earliest Christian architecture can provide us with a reliable picture of the transformations that triggered the end of classical society in Baetica, and that these changes happened faster and deeper than is generally admitted. In less than eighty years, a new architecture emerged that transformed cities and the countryside. Basilicas consecrated to the martyrs took over the necropolises. Churches and cemeteries arose in urban centres, on forums and baths, whose pagan decoration was destroyed. Episcopal complexes occupied large areas of the city. Monasteries controlled Roman roads and developed important economic activities.

The Church was one of the main protagonists of these transformations, and demonstrated its power through an architecture that modified the landscape. This power was exercised by the figure of the bishop, as if he were the ruler of a small state, anticipating what is often considered a particularly medieval phenomenon. These bishops belonged to local aristocratic elites, and even formed episcopal dynasties. Archaeological, epigraphic, and numismatic data confirm the importance of episcopal control over society, politics, and the economy.