De concordia mensium atque elementorum (Byrhtferth’s diagram)

  • Latin
  • diagram, prose
  • Anglo-Latin texts, diagrams
Elaborate diagram of the ‘harmony of the months and elements’, which once occupied a single page in a largely computistical manuscript compiled by Byrhtferth of Ramsey (c. 970–c. 1020). The original of this compilation is lost, but two independent ‘copies’ made in the early 12th century remain. The diagram aligns different aspects of time (solstice, equinox, months, seasons, ages of man), the zodiac and the four elements, and in this way, introduces a number of key concepts relevant to computus. In the Oxford manuscript, the diagram comes right at the end of a section (ff. 3r-7v) which contains a miscellaneous variety of short texts and visual designs related to computus, and directly precedes another section (ff. 8r-15v) containing tables and texts on computus.
A feature of Irish interest is found in the Oxford manuscript only: in the middle of the diagram, just above the central wheel with its spokes, there is a horizontal bar of cryptic symbols, which concludes with a series of ogham characters. Their meaning is unclear, although Patrick Sims-Williams, ‘Byrhtferth’s ogam signature’ in Ysgrifau a cherddi cyflwynedig i Daniel Huws... (1994) has argued that it may be a cryptogram of Byrhtferth’s signature (transliterated as Bryht-ferð me fecit). It is also unclear whether the ogham notation was part of Byrhtferth’s original design or that it is due to later Irish influence on the Oxford manuscript or its intermediate exemplar.(2)n. 2 Irish influence is also demonstrated by the list of Irish names for days of the week on f. 71v (ed. Dáibhí Ó Cróinín, ‘The oldest Irish names for the days of the week?’, Ériu 32 (1981)).
De concordia mensium atque elementorum (Byrhtferth’s diagram)
Also referred to in English as ‘The physical and physiological fours’.(1)n. 1 Charles and Dorothy Singer, 1919.
Ascribed to: Byrhtferth of RamseyByrhtferth of Ramsey
(c. 970–c. 1020)
English monk and scholar
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It is attributed to Byrhtferth in the Oxford manuscript (Hanc figuram edidit Bryhtferð monachus).
  • Oxford, St John's College, MS 17 [c. 1110]
    f. 7v
    Provenance: Thorney/Ramsey. Here attributed to Byrhtferth.
  • London, British Library, MS Harley 3667
    f. 8r
    Provenance: Peterborough. The manuscript belongs with a part of London, British Library, MS Cotton Tiberius C i.
  • Latin
diagram, prose (primary)


Anglo-Latin texts



Charles and Dorothy Singer, 1919.
Irish influence is also demonstrated by the list of Irish names for days of the week on f. 71v (ed. Dáibhí Ó Cróinín, ‘The oldest Irish names for the days of the week?’, Ériu 32 (1981)).

Primary sources Text editions and/or modern translations – in whole or in part – along with publications containing additions and corrections, if known. Diplomatic editions, facsimiles and digital image reproductions of the manuscripts are not always listed here but may be found in entries for the relevant manuscripts. For historical purposes, early editions, transcriptions and translations are not excluded, even if their reliability does not meet modern standards.

[ed.] Baker, Peter S., and Michael Lapidge, Byrhtferth’s Enchiridion, Early English Text Society 15, Oxford: Oxford University Press, 1995.
374 (Appendix A)
The calendar and the cloister: Oxford, St John's College MS 17, Online: McGill University Library, Digital Collections Program. URL: <http://digital.library.mcgill.ca/ms-17/>. 
The calendar and the cloister is a scholarly resource devoted to a single medieval manuscript: Oxford, St John's College 17. This splendid volume was created in the first decade of the 12th century at Thorney Abbey, a Benedictine monastery in Cambridgeshire. Its importance for the cultural and intellectual history of Anglo-Saxon and Anglo-Norman England has been recognized since the 16th century by historians, philologists, and scholars working in the fields of medieval science, monastic culture, and the history of the book.

Secondary sources (select)

Baker, Peter S., “More diagrams by Byrhtferth of Ramsey”, in: O'Brien O'Keeffe, Katherine, and Andy Orchard (eds), Latin learning and English lore: studies in Anglo-Saxon literature for Michael Lapidge, 2 vols, vol. 2, Toronto Old English Studies, Toronto: University of Toronto Press, 2005. 53–73.
C. A.,Dennis Groenewegen