Teacher and Computist

Within the walls of Jarrow, Bede was the master of the monastic school, and a large part of his output was written to be taught: textbooks on spelling, metre, figures of speech, and the natural world, and the two works on the reckoning of time that made him the standard authority of the medieval West on the calendar. This file treats Bede the teacher and, above all, the computist — the science of calculating the date of Easter, the Dionysian reckoning he championed, and why the unity of the Church’s calendar was for him a matter of more than arithmetic.

Tradition: Pan-Orthodox (pre-Schism; Doctor of the Church; the Father of English History)

The Schoolmaster of Jarrow

Bede was, before and beneath everything else, a teacher. He entered the monastery at seven, was ordained deacon at nineteen and priest at thirty, and spent the rest of his life within the community, where one of his settled duties was the instruction of the younger monks (HE 5.24; Colgrave & Mynors 1969; Ward 1990). The school of Wearmouth-Jarrow trained generation after generation of Northumbrian monks, and one of its pupils, Cuthbert — later abbot of the house — is the eyewitness who describes Bede teaching and dictating to the very end of his life, in the Letter on the Death of Bede (Cuthbert, Epistola de obitu Bedae; in Colgrave & Mynors 1969). A significant portion of Bede’s writing was generated directly by this pedagogical work: he composed the elementary textbooks his students needed because the books he had inherited were either too advanced, too pagan, or simply lacking, and he wrote them to be used in the classroom of his own monastery (Brown 2009; DeGregorio 2010, Irvine and others on Bede’s educational works).

These schoolbooks are modest in appearance but historically important, because through them Bede shaped the curriculum of the early medieval West. The condition that produced them is worth stating plainly: in Northumbria Latin was nobody’s mother tongue. The monks were Anglo-Saxons learning a foreign sacred language from books, and the elementary aids a Roman or Italian schoolroom could take for granted had to be supplied afresh, often by stripping the pagan illustrations out of the inherited grammars and replacing them with examples a Christian monk could safely use (Brown 2009; DeGregorio 2010). Bede’s textbooks are the response of a working teacher to exactly this need. De orthographia is a reference work on the correct spelling and use of Latin words, arranged alphabetically — a help for monks whose native tongue was not Latin and who had to write it correctly for the liturgy and the copying of texts (Bede, De orthographia; Brown 2009). De arte metrica, on the art of Latin metre, taught the scansion of verse and was paired with De schematibus et tropis, on the figures of speech and tropes, which Bede illustrated pointedly from Scripture rather than from the classical poets — arguing that the rhetorical devices the pagans prized were found first and best in the sacred text (Bede, De arte metrica; De schematibus et tropis; Brown 2009; DeGregorio 2010). De natura rerum, “On the Nature of Things,” is a short handbook of cosmology and natural science — the heavens, the elements, the earth, weather, tides — drawn largely from Isidore and Pliny but corrected and reorganized by Bede, and it shows the same instinct: to gather what was known, set it in order, and make it teachable (Bede, De natura rerum; Laistner 1935; Wallis 1999, introduction). Together these works constitute a small, coherent curriculum, and their wide later circulation made Bede a schoolmaster to the whole Latin West long after his death.

The Computus and the Reckoning of Time

The summit of Bede’s didactic and scientific writing is the computus — the body of technical knowledge required to construct and understand the Christian calendar, and above all to calculate the date of Easter. Bede wrote two works on it. The earlier, De temporibus (“On Times”), is a brief treatise of 703 that sets out the elements of time-reckoning and ends with a short world-chronicle. The later and far greater work, De temporum ratione (“On the Reckoning of Time”), completed in 725, is a full and systematic treatment in seventy-one chapters that became the standard medieval textbook on the calendar and was copied and glossed for centuries (Wallis 1999, introduction; Brown 2009). [Disputed: the dating of these works follows the standard scholarly chronology — *De temporibus* to 703 and *De temporum ratione* to 725 — which is itself derived from the *anni* Bede gives in the world-chronicles attached to each; Wallis (1999, introduction) and Brown (2009) adopt these dates, while noting that they rest on Bede's own internal reckoning rather than on external testimony.]

What the computus had to coordinate was genuinely difficult. The Christian liturgical year runs on two clocks at once: the solar year of the sun, which governs the fixed feasts and the seasons, and the lunar month of the moon, which governs Easter and the feasts that depend on it. Bede’s De temporum ratione works systematically up from the smallest units — the moment, the hour, the day — through the week, the month, the seasons, and the year, to the great cycles by which sun and moon are reconciled, and finally to the ages of the world (De temporum ratione 1–71; trans. Wallis 1999). Along the way Bede gives the most careful Latin discussion yet written of the lunar calendar, the leap-year correction, the saltus lunae (the “leap of the moon” needed to keep the lunar reckoning in step), the calculation of the moon’s age and phase, and the doctrine of the tides, which Bede uniquely connected to the moon and even noted varied by locality along a coast (De temporum ratione 29, on the tides; chs. 19–43 on the lunar reckoning; Wallis 1999, commentary). His grasp of the underlying astronomy, working only from Latin authorities and naked-eye observation, is the most impressive scientific achievement of the early medieval West.

The Date of Easter

The whole apparatus existed to serve one calculation: the date of Pascha, the Christian Easter, the moveable feast on which the entire variable part of the liturgical year hangs. The rule the Church had settled on was that Easter is the first Sunday after the first full moon falling on or after the spring (vernal) equinox — a rule that holds Easter to the Sunday of the Resurrection while binding it to the Passover full moon of the Jewish calendar in which the events fell, and to the equinox as the boundary of spring (De temporum ratione 59–61, on the Paschal full moon and the equinox; Wallis 1999; Bede, HE 5.21). Because the lunar months do not divide evenly into the solar year, the full moons fall on different solar dates each year, and the date of Easter therefore moves; to predict it years in advance, the computists used the nineteen-year Metonic cycle, the discovery that 235 lunar months return very nearly to the same alignment with 19 solar years, after which the cycle of moon-dates repeats. Bede expounds the nineteen-year cycle and the great Paschal tables built upon it in detail, and it is the backbone of his treatment (De temporum ratione 56, on the nineteen-year cycle; chs. 44–65 on the Paschal calculation; Wallis 1999, commentary).

The tables Bede taught and defended were those of Dionysius Exiguus, the sixth-century Roman monk who had adapted the Alexandrian Paschal reckoning — the system of the Church of Alexandria, which had long been the most expert in this science — for use in the West, extending the cycle and tying it to the Anno Domini era he had devised (De temporum ratione 47–49, 65; Wallis 1999, introduction and commentary; Brown 2009). The Alexandrian reckoning placed the vernal equinox at 21 March and fixed the lunar limits within which the Paschal full moon must fall, and it was these conventions — not the differing equinox-date and lunar limits of the older Roman and Insular tables — that Dionysius transmitted to the West and that Bede made canonical for his readers (De temporum ratione 30, on the equinox; chs. 59–61; Wallis 1999, commentary). This Roman-Alexandrian, or Dionysian, reckoning was the system Bede championed throughout his work, and his advocacy was not merely technical. For Bede the correct calculation of Easter was bound up with the unity and catholicity of the Church: a community that kept Easter on the wrong date was, in effect, out of communion with the rest of Christendom on the very feast of the Resurrection, celebrating while others fasted, or fasting while others rejoiced (HE 3.25; 5.21; Colgrave & Mynors 1969).

Whitby and the Insular Reckoning

This conviction had a sharp local history, which Bede narrates and which his computus presupposes. The Irish and British churches of the Insular world had long used an older Paschal table, the 84-year cycle sometimes called the “Celtic” reckoning, together with a different rule for the equinox and the permissible lunar limits; the result was that in some years the Celtic churches and the Roman party in Britain kept Easter on different Sundays (HE 3.25; 3.4; Colgrave & Mynors 1969; Wallis 1999, introduction). Bede records, with evident feeling, that this produced the scandal of King Oswiu of Northumbria keeping Easter while his queen, trained in the Roman usage, was still in the Lenten fast of Palm Sunday (HE 3.25; Colgrave & Mynors 1969). The matter was brought to decision at the Synod of Whitby in 664, where, in Bede’s account, Wilfrid argued the Roman case and Colmán of Lindisfarne the Irish, and King Oswiu ruled for the Roman observance — after which Colmán, unwilling to abandon the tradition of his elders, withdrew to Iona and then to Ireland (HE 3.25–26; Colgrave & Mynors 1969; see St. Colman of Lindisfarne and St. Aidan of Lindisfarne). Whitby decided the question for Northumbria; the wider Insular world conformed only gradually, Iona itself accepting the new reckoning early in the eighth century.

Bede’s own computistical works are, in part, the technical consolidation of the Roman victory at Whitby — they put into the hands of every monastery the means to calculate Easter correctly by the Dionysian tables, so that the disputes of the previous century need never recur. But Bede’s treatment is notably free of triumphalism toward the men who had erred. He praises Aidan and the Irish missionaries warmly even while faulting their Paschal reckoning, observing that they kept Easter wrongly only because they had received no better instruction, and honouring their holiness of life (HE 3.3–5, 3.17, 3.25–26; Colgrave & Mynors 1969). The error, for Bede, was real and mattered; the men who held it in good faith were not thereby unholy.

The Letter of Ceolfrith to Nechtan

The clearest single statement of why the Easter question mattered to Bede — and of how the case for the Roman reckoning was made to those who still followed the old way — is the long letter he preserves in the Ecclesiastical History, written in the name of Abbot Ceolfrith of Wearmouth-Jarrow to the Pictish king Nechtan, who had asked for instruction (HE 5.21; Colgrave & Mynors 1969). The letter, very probably drafted by Bede himself, lays out the whole case: the scriptural and computistical grounds for the equinox and the Paschal full moon, the reasons the 84-year cycle was defective, and the theological argument that the unity of the Church required a common observance of the feast of the Resurrection (HE 5.21; Wallis 1999, introduction; Brown 2009). King Nechtan accepted the argument and brought the Pictish church into conformity — a victory Bede records with satisfaction as the near-completion of the long process by which the churches of Britain came into a single Paschal communion (HE 5.21–22; Colgrave & Mynors 1969).

For Bede, then, the computus was never merely arithmetic. The reckoning of time was a sacred science because time itself was the medium of salvation history, ordered by God from the creation to the consummation, and the calendar was the Church’s faithful keeping of that order (De temporum ratione, especially the closing chapters on the ages of the world, chs. 66–71; Wallis 1999; see The World Chronicle and Eschatology). To compute Easter rightly was to keep the feast of the Resurrection in unity with the whole Church, and the unity of the Church’s calendar — the common observance that holds all the local churches to one rhythm of fast and feast — was a visible expression of the communion of the one Body (see The Church Calendar). The same concern carried forward into Bede’s popularization of the Anno Domini era and his chronology of the world ages, treated in their own section (see Anno Domini and the Computus). Through these works the small monastery on the Tyne taught the medieval West not only how to spell and scan, but how to count the years of the Lord and to keep His Pascha in common.

References

Bede. The Reckoning of Time (De temporum ratione). Trans. Faith Wallis. Translated Texts for Historians 29. Liverpool: Liverpool University Press, 1999. (Cited by chapter: the units and cycles of time, chs. 1–43; the Paschal calculation and the nineteen-year cycle, chs. 44–65; the tides, ch. 29; the ages of the world, chs. 66–71; with Wallis’s introduction and commentary on the computus, the Dionysian tables, and the dating of the works.)
Bede. On Times (De temporibus), 703. Cited by chapter; the earlier and briefer computus, with its world-chronicle.
Bede. De natura rerum, De arte metrica, De schematibus et tropis, De orthographia. The educational textbooks; cited by title.
Bede. Ecclesiastical History of the English People (Historia ecclesiastica gentis Anglorum). Ed. and trans. Bertram Colgrave and R. A. B. Mynors. Oxford Medieval Texts. Oxford: Clarendon Press, 1969. (The Synod of Whitby and the Easter dispute at HE 3.25–26; Aidan and the Irish at HE 3.3–5, 3.17; the letter of Ceolfrith to Nechtan and the equinox/Paschal rule at HE 5.21; the autobiographical note at HE 5.24.)
Cuthbert. Letter on the Death of Bede (Epistola de obitu Bedae). In Colgrave & Mynors, Bede’s Ecclesiastical History (1969), 579–587. (Bede teaching and dictating to the end.)
Laistner, M. L. W. “The Library of the Venerable Bede.” In Bede: His Life, Times, and Writings, ed. A. Hamilton Thompson, 237–266. Oxford: Clarendon Press, 1935.
Brown, George Hardin. A Companion to Bede. Woodbridge: Boydell Press, 2009.
DeGregorio, Scott, ed. The Cambridge Companion to Bede. Cambridge: Cambridge University Press, 2010.
Wallis, Faith. Bede: The Reckoning of Time. Translated Texts for Historians 29. Liverpool: Liverpool University Press, 1999. (Introduction and commentary, on the computus, the Easter controversy, the Dionysian and Alexandrian reckoning, and the dating of Bede’s works.)
Ward, Benedicta. The Venerable Bede. London: Geoffrey Chapman, 1990.