A rigorous, source-critical biography reconstructs the life and missionary activity of the figure traditionally called St. Patrick, examining his capture and escape, religious formation in Gaul and Britain, consecration, and work in Ireland. It situates those events within the island's political and social landscape, contrasts legend with documentary evidence, and addresses related figures such as Palladius. Extensive appendices and maps present the textual criticism, source debates, and cautious reconstructions that underpin the narrative while acknowledging persistent uncertainties and hypotheses.