and entered the Cistercian order ca. 1125. He was chosen abbot of Igny in 1138. He is
best known for his fifty-four sermons on the feasts of the liturgical year, which
demonstrate a mastery of Scripture. Guerric preached a contemplative theology that
emphasized Christ’s coming into humans in his “spiritual form,” as supernatural guide
and life-giving grace. Especially important are Guerric’s insistence on Mary’s maternal
role in this in-forming of Christ in humankind and his presentation of the process of
illumination in the spiritual development of the individual.
Grover A.Zinn
Guerric d’Igny. Sermons. PL 185.11–214.
——. Liturgical Sermons, trans. the Monks of Mount Saint Bernard Abbey. 2 vols. Spencer:
Cistercian, 1970–71.
Bouyer, Louis. The Cistercian Heritage, trans. Elizabeth A. Livingstone. Westminster: Newman,
1958, pp. 190–203.
GUESCLIN, BERTRAND DU
(ca. 1320–1380). Constable of France. Bertrand du Guesclin, perhaps the most famous
French warrior of the Hundred Years’ War, was the first of three distinguished Breton
noblemen to serve as constable of France during this conflict. Du Guesclin was born into
an old but not very wealthy family. In 1353, he succeeded his father as lord of Broons
and a year later was knighted. He began serving the French crown at Pontorson as early
as 1351, and for the next thirteen years his military career was confined to Normandy,
where he fought for the king against the supporters of Charles the Bad, king of Navarre,
and Brittany, where he fought for Charles de Blois against Jean de Montfort, the English-
backed claimant to the duchy. In 1357, he led the forces that supplied the besieged city of
Rennes. In May 1364, he won a great victory over the Navarrese forces at Cocherel in
Normandy after feigning a withdrawal that induced his foes to abandon a superior
position. In the same period, he also suffered defeats, as the English captured him at Pas
d’Évran in 1359, at the bridge of Juigne in 1360, and at Auray in 1364. In this last battle,
Charles de Blois was killed and Montfort became duke of Brittany.
With Normandy and Brittany now pacified, Du Guesclin devoted the rest of the 1360s
to service in southern France and Spain. Louis of Anjou, brother of Charles V, was royal
lieutenant in Languedoc and needed him to lead numerous routiers (unemployed
soldiers) outside the realm on campaigns in Provence and Castile. His successful
expedition to Spain in 1365 was followed by his defeat and capture at Nájera in 1367. In
1369, however, he returned to Spain and reinstalled a pro-French king on the Castilian
throne.
Rarely successful at pitched battles, Du Guesclin was adept at handling bands of
routiers and fighting with their tactics. In 1370, when a routier chieftain, Robert Knolles,
was leading an English raid into northwestern France, Charles V summoned Du Guesclin
and made him constable. The latter then made a private alliance with Olivier de Clisson,
a wealthy Breton lord who had fought against him at Auray and Nájera. Clisson brought
powerful contingents of Bretons into the French army, and he and Du Guesclin
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