Seán Mac Donnchadha is an Irish historian and writer specialising in the ecclesiastical and political history of late antiquity and the early medieval period. Drawing on Ireland's own deep tradition of engagement with the Latin church, he has written extensively on the institutional development of early Christianity, the theological controversies that shaped the medieval West, and the often-overlooked regional histories that lie beneath the surface of the familiar grand narratives. His work is characterised by narrative rigour, accessibility to the general reader, and a particular interest in the long-term consequences of moments when ordinary communities made extraordinary institutional decisions. He lives and writes in Ireland.