This book explores the vibrant and interconnected world of early Christianity through the lens of mobility, communication, and urban leadership. Tracing the journeys of apostles, missionaries, and co-workers like Paul, Priscilla and Aquila, and Ignatius of Antioch, it reveals how early Christian leaders navigated the sprawling cities of the Roman Empire to build resilient networks of faith and fellowship. By examining the critical role of letters as tools of governance and unity, the practice of hospitality as social and spiritual sustenance, and the emerging structures of authority centered in urban congregations, the study uncovers how scattered communities maintained doctrinal coherence and communal identity across diverse cultural and geographic landscapes. Combining detailed historical analysis with theological reflection, the book illuminates the dynamic processes through which early Christianity transformed from a localized sect into a universal Church, rooted in shared language, ritual, and memory. A scholarly contribution to the history of Christianity, it offers fresh insights into the social fabric and leadership dynamics that underpinned the faith's expansion.