“White Strangers”: By the end of the 8th century, Viking raiders were terrorizing monasteries and communities in Ireland and Britain, and were known by the Irish as Finngaill and Dubgaill — the Norwegian “white strangers” and the Danish “dark strangers.”

The title “To the Extent a Tradition Can Be Said to Be Developed . . .” appears in a footnote to the introduction to The Theology of Arithmetic, by Iamblichus, translated by Robin Waterfield (Phanes Press, 1988). The poem draws its numerical assignments from “The Alphabet of Devotion” in Iona: The Earliest Poetry of a Celtic Monastery by Gilbert Màrkus and Thomas Owen Clancy (Edinburgh University Press, 1995), and “Dark Night of the Soul,” by the 16th-century mystic St. John of the Cross, translated by David Lewis (Thomas Baker, 1908).

The third “Song” uses an idea from Picard’s The World of Silence.

The Mighty Warriors Intercessors Prayer Army is an online division of Benny Hinn Ministries. The italicized passage revises a fragment from Pope Gregory the Great’s letter to the monks he sent to preach to the British in the 6th century. The fifth stanza’s final lines draw from Revelations of Divine Love, by Julian of Norwich (Penguin, 1999).

Lines referencing Edinburgh’s United Glass Ltd. are inspired by the online article “Some recollections by Archie Young Jnr, works’ engineer (1962–1967),” edited by Christine Hudson.

The “two kinds of darkness” of “The Isle of May lies just outside . . .” are from Dionysius the Areopagite.

Line 19 of “The Hermits” is Dianne Brodie’s.

ACKNOWLEDGEMENTS

My sincere thanks to the editors of the publications in which these poems, in earlier versions, appeared:

Times Literary Supplement: “Tentsmuir Forest,” “A Lesson,” “You Can’t Go Back,” “Clarity.”

New England Review: “A Retreat,” “Two Chapters on Ancient Stones,” “Stinging Nettle Appreciation.”

Ambit: “Whose Deaths Were Recorded Officially as Casualties of ‘The Battle of May Island.’”

Poetry London: “Ancient Remedies with Contemporary Applications Currently in Development.”

Lemon Hound: “To the Extent a Tradition Can Be Said to Be Developed; It Is More Accurate to Say It Can Be Clothed in Different Forms.”

The Forward Book of Poetry 2018: The Best Poems From the Forward Prizes: “An Enthusiast.”

POETRY: “The Hermits.”

Swimmers: “Origin Story,” “Kentigern and the Robin.”

Granta: “The Sharing Economy,” “A Plenitude,” “A Trawlerman.”

Wild Court: “He remembers a friend from his travels,” “Evidence of his own cult in Pictland exists in the distribution of carved stones bearing his name.”

London Review of Books: “An Enthusiast,” “Crail Autumn,” “Crail Spring,” “A Miscalculation.”

The Paris Review: “When Solitude Was a Problem, I Had No Solitude.”

The Walrus: “The Desert Fathers,” “The Shags, Whose Conservation Status Is ‘of Least Concern.’”

Harper’s Magazine: “The North.”

The Scores: “Sauchope Links Caravan Park,” “The Spies,” “Intercessors,” “The North.”

Prac Crit: “Mercenaries Know There’s Always Room for Specialists in the Market.”

Thanks to Carleton Wilson and Junction Books, which published early versions of some of these poems in one of its beautifully designed chapbooks, under the title Retreats.