of Abbo of Fleury during Abbo’s visit to England in
985–87. Byrhtferth’s varied literary career appears to
have begun shortly after the departure of that great
scholar. His works fall into three genres: computistical,
hagiographical, and historical.
Computus
Computus (OE gerim, gerimcræft) is the science of
computation as it relates to the ecclesiastical calendar.
The word can also be used of any collection of short texts
on that science; these generally contained a calendar
accompanied by tables and instructions for performing
such tasks as fi nding the moon’s age and calculating the
dates of movable feasts.
The earliest of the datable works associated with
Byrhtferth is a compilation of materials on computus. Of
the three copies of this compilation all are incomplete,
and two were evidently revised or augmented at later
periods. The version that seems closest to Byrhtferth’s
is in Oxford, St. John’s College 17, a large and elegant
manuscript written around 1110–11 at the nearby Ab-
bey of Thorney. This manuscript contains, among other
items, several computistical works by Bede and Helperic
and a computus, all accompanied by extensive marginal
glosses and introduced by a Latin Epilogus (“preface”)
by Byrhtferth. Several passages in the computus and
glosses date the compilation (leaving aside those items
that postdate Byrhtferth) to the years 988–96. Apart from
the Epilogus the only item in the compilation attributed
to Byrhtferth is a full-page diagram illustrating the har-
mony of the universe, and suggesting correspondences
among cosmological, numerological, and physiological
aspects of the world. Though other, minor items in St.
John’s 17 may well be by Byrhtferth, their authorship
cannot be proved; nor can it be proved beyond doubt
that he was responsible for the compilation as a whole.
But the date of the compilation, the presence in it of the
Epilogus and diagram, and its close association with
the Enchiridion, discussed below, make it likely that
Byrhtferth built it up from a smaller compilation left
behind at Ramsey by his teacher Abbo.
Byrhtferth’s Enchiridion (also called his Manual),
preserved in a single manuscript, Bodl. Ashmole 328,
can be dated from internal evidence to the year 1011.
Written in Latin and OE, it treats a variety of subjects;
however, the largest part of it is a guide to the use of
the computus. The fi rst three of the four books of the
Enchiridion take the student step by step through a
computus evidently similar to the one in St. John’s 17,
introducing its tables and the calendar with explana-
tions drawn largely from Helperic, Hrabanus Maurus,
and Bede. Byrhtferth frequently digresses from the
computus to touch on matters as diverse as the orga-
nization of the universe, elision of syllables in Latin
verse, and rhetorical fi gures and diacritics. Book Four
of the Enchiridion is a clearly presented Latin treatise
on number symbolism, the fullest statement anywhere
in Byrhtferth’s writings of his belief that the divine
order of the universe can be perceived through the
study of numbers; it is also an excellent general source
for the modern student interested in medieval number
symbolism.
The last of Byrhtferth’s works on computus is an
unsigned fragment of an OE text preserved in BL Cot-
ton Caligula A.xv, fols. 142v–l43r; his authorship of the
fragment is suggested by its stylistic similarity to the
OE of the Enchiridion.Hagiography
Two Latin saints’ lives have been attributed to Byrhtferth
on the basis of their stylistic affi nity with the Latin of
his signed works, the Epilogus and Enchiridion. These
works, the Life of St. Oswald and the Life of St. Ec-
gwine, are preserved together in a single manuscript,
BL Cotton Nero E.i, a large passional to which they
were added in the last half of the 11th century. Both
the original passional and the additions were written
at Worcester.
The Life of St. Oswald, written between 996 and
1005, details the career of the bishop of Worcester and
archbishop of York who, with Dunstan and Æthelwold,
was one of the leaders of the Benedictine Reform of
the 10th century; Byrhtferth’s work is considered the
most important source for his life. The Life is also cited
as a historical source for the murder of King Edward
in 978 and, more famously, for the Battle of Maldon
in 991. However, the Life tells us little about the latter
two incidents that we cannot learn from other sources,
and historians have at times shown impatience with its
lack of circumstantial detail—forgetting, perhaps, that
hagiographers, unlike chroniclers, were interested less
in events themselves than in their theological signifi -
cance.
The danger of using saints’ lives as historical sources
is perhaps nowhere better illustrated than in Byrhtferth’s
Life of St. Ecgwine, written after the year 1000, evidently
at the request of the monks of Evesham, the monastery
that Ecgwine, as bishop of Worcester, had founded
around the beginning of the 8th century. While Byrht-
ferth could draw on a wealth of documentary evidence,
eyewitness report, and personal recollection in writing
about St. Oswald, with Ecgwine he had no documents
beyond a spurious charter and an irrelevant letter; all
other evidence was fi ltered through some two centuries
of oral tradition. It is no surprise, then, that Ecgwine
emerges as an utterly conventional saint and that paral-
lels for the incidents of his life can generally be found
in the lives of other, equally conventional saints.BYRHTFERTH