The study of Paleochristian churches in Italy opens a window onto a world in transformation, a world in which the architectural, social, and spiritual landscapes of the Roman Empire were being reshaped by the emergence of Christianity as a public, institutionalized religion. To write the history of these early churches is to trace the evolution of a faith community from marginality to prominence, from clandestine gatherings in private homes to the construction of monumental basilicas that would define the visual and liturgical vocabulary of Western Christianity for centuries. Italy, as the administrative and symbolic heart of the empire, became the principal stage on which this transformation unfolded. The material remains of its early Christian buildings-fragmentary, altered, or miraculously preserved-constitute a corpus of evidence that allows us to reconstruct not only architectural forms but also the lived experience of the communities that built and used them.