They may be coated in layers of myth and pious anecdote but dig deep enough and the pioneering leaders of Celtic Christianity are revealed as reassuringly human individuals, responding to their faith by deliberately living on the edges of society.

From the goddess-nun Brigid and absent-minded Cainnech to severe ascetics such as Columbanus and Baldred, together they demonstrate a close connection with the natural world, an astonishing self-discipline and, above all, a rigorous commitment to what it meant to be 'pilgrims for Christ'. Establishing a network of influential monastic communities, they travelled from the territories of the Atlantic seaboard – Ireland, Wales and Cornwall – across Scotland, the north of England and deep into continental Europe, transforming the religious experience of all they encountered.