naventure: Editiones Instituti Franciscani Universitatis S.
Bonaventurae, 1967–86.
——. Opera politica, ed. Jeffrey G. Sikes et al 3 vols. Manchester:
University of Manchester Press, 1940–.
——. William of Ockham. Philosophical Writings: A Selection,
ed. and trans. Philotheus Boehner. rev. ed. Stephen F. Brown.
Indianapolis: Hackett, 1990.
Adams, Marilyn McCord. William Ockham.2 vols. Notre Dame:
University of Notre Dame Press, 1987.
Baudry, León. Guillaume d’Occam: sa vie, ses æuvres, ses idées
sociales et politiques. Paris: Vrin, 1949, Vol. 1: L’homme et
les æuvres.
Boehner, Philotheus. Collected Articles on Ockham, ed. Eligii M.
Buytaert. St. Bonaventure: Franciscan Institute, 1958.
McGrade, Arthur Stephen. The Political Thought of William
of Ockham: Personal and Institutional Principles. London:
Cambridge University Press, 1974.
Moody, Emest A. The Logic of William Ockham. London: Sheed
and Ward, 1935.
H. Lawrence Bond
OFFA (r. 757–96)
King of Mercia in 757, after ousting another claimant.
By the time of his death on 28 July 796 Offa also held
sway over Sussex, Kent, and East Anglia. His daughters
married rulers of Wessex and Northumbria, thus extend-
ing his sphere of infl uence. He clashed with the Welsh,
which probably led him to construct the dike that bears
his name. Running along much of the nearly 150 miles
of the Welsh frontier, from the Severn estuary to a few
miles south of the Dee estuary, Offa’s Dyke is the longest
earthwork in Britain. It could have been planned in one
season and completed in the next; if this was indeed so,
it is testimony to the organizational and coercive power
that made him the leading English ruler of his day.
Offa utilized the church to enhance his power. He
persuaded Pope Hadrian to sanction the creation of a
new archdiocese at Lichfi eld in 787, only a few miles
from his palace at Tamworth, thus effectively neutral-
izing the hostile archbishop of Canterbury. Probably
imitating Charlemagne, he had his son, Ecgfrith, con-
secrated as his successor in 787, the fi rst royal anointing
in English history.
Offa seems to have had extensive trade contacts
with the Carolingian realm, which in turn appears to
have made monetary reform possible. His silver penny,
infl uenced by a Carolingian model, was the basis of the
English coinage until the reign of Henry III. He appreci-
ated the coin’s potential for symbolism; many bear his
name and a fi nely wrought effi gy, and some even carry
the likeness of his wife, Cynethryth, a practice drawn ei-
ther from Byzantine Italy or even late-imperial Rome.
The poems Beowulf and Widsith, a tribute list known
as “The Tribal Hidage”—even the origin of a system of
burghal defense later associated with Alfred the Great of
Wessex—have been associated with Offa. Much more
research will be needed, however, before a balanced
assessment of the cultural and social contributions of
his reign can be made.
Though his achievements did not long survive him,
he was regarded as a great fi gure in the Middle Ages.
Alfred claimed to have adopted and modifi ed his laws; a
sword reputed to be his was still treasured two centuries
after his death; a 14th-century Life was composed by the
monks of St. Albans, who revered him as their founder.
An imitator rather than an innovator; his image of great-
ness derived from his longevity, ruthlessness, and astute
ability to exploit the imagery of rulership. Apart from
the dike little evidence of his power survives; the Mer-
cian archives are lost, as is his burial place. His palace
at Tamworm probably lies under the parish churchyard
and so cannot be excavated.Further Reading
Blunt, Christopher E. “The Coinage of Offa.” In Anglo-Saxon
Coins: Studies Presented to F.M. Stenton on the Occasion
of His 80th Birthday, ed. R.H.M. Dolley. London: Methuen,
1961, pp. 39–62.
Brooks, Nicholas. “The Development of Military Obligations in
Eighth- and Ninth-Century England.” In England before the
Conquest: Studies in Primary Sources Presented to Dorothy
Whitelock, ed. Peter Clemoes and Kathleen Hughes. Cam-
bridge: Cambridge University Press, 1971, pp. 69–84.
Hart, Cyril. “The Kingdom of Mercia.” In Mercian Studies, ed.
Ann Dornier. Leicester: Leicester University Press, 1977,
pp. 43–61.
Keynes, Simon. “Changing Faces: Offa, King of Mercia.” History
Today 40/11 (November 1990): 14–19.
Levison, Wilhelm. England and the Continent in the Eighth
Century. Oxford: Clarendon, 1946.
Noble, Frank. Offa’s Dyke Reviewed. Ed. Margaret Gelling. BAR
Brit. Ser. 114. Oxford: BAR, 1983.
Stenton, F.M. “The Supremacy of the Mercian Kings.” In Prepa-
ratory to Anglo-Saxon England, ed. Doris M. Stenton. Oxford:
Clarendon, 1970, pp. 48–66.
Wormald, Patrick. “The Age of Offa and Alcuin.” In The Anglo-
Saxons, ed, James Campbell. Oxford: Phaidon, 1982, pp.
101–31.
Wormald, Patrick. “In Search of King Offa’s “Law-Code.” In
People and Places in Northern Europe 500—1600: Essays
in Honour of Peter Hayes Sawyer, ed. Ian Wood and Niels
Lund. Woodbridge: Boydell, 1991, pp. 25–45.
David A.E. PelteretÓLÁFR TRYGGVASON
(r. 995-999/1000)
Óláfr Tryggvason was king of Norway 995–999/1000.
He was the son of Tryggvi Óláfsson, grandson of Haraldr
hárfagri (“fair-hair”) Hálfdanarson, a petty king of Viken
or the Upplands.
Before Óláfr Tryggvason became king, he led great
Viking raids to England, Scotland, and Ireland. The
Anglo-Saxon Chronicle for the years 991 and 994 states
that Óláfr led a large Viking fl eet to attack the easternÓLÁFR TRYGGVASON