In 1047 Duke William II of Normandy, about nineteen and barely in control of his own duchy, joined his overlord Henry I of France to defeat a rebellion of the viscounts of the Bessin and the Cotentin at Val-ès-Dunes east of Caen. The victory ended the anarchy of his minority and began the consolidation that made Normandy strong enough to invade England.
Val-ès-Dunes was fought in 1047 on open ground east of Caen, between the young Duke William II of Normandy supported by his overlord King Henry I of France, and a confederacy of the viscounts of western Normandy who wanted him replaced by his cousin Guy of Burgundy. The rebels were broken and driven back towards the Orne, where the sources say many drowned at the crossings.
It was not a large battle by the standards of the century, and it did not end resistance at a stroke — Brionne held out for years afterwards, and William spent the 1050s fighting Anjou and eventually the same King Henry who saved him here. What it ended was the possibility that the duchy would dissolve. From 1047 William was a duke who could enforce his will, and nineteen years later that duchy launched the invasion of England.
William became duke in 1035, aged about eight, when his father Robert I died at Nicaea on the way back from Jerusalem. He was illegitimate, the son of Herleva of Falaise, and his succession depended on oaths Robert had extracted from the Norman magnates before he left. Those oaths held only as long as the men who guaranteed them lived.
They did not live long. His guardian Alan of Brittany died in 1040, probably poisoned; Gilbert of Brionne was murdered; Turchetil was killed; and Osbern the steward had his throat cut in the duke’s own chamber at Vaudreuil while the boy slept nearby. The ducal demesne was plundered, castles went up without licence, and private war became normal. The Normandy of these years was not a principality in crisis so much as a collection of lordships doing as they pleased.
By 1046 the western lords had settled on a candidate. Guy of Burgundy was William’s first cousin through his aunt Adeliza, held Brionne and Vernon by William’s own grant, and had a legitimate birth to set against the duke’s bastardy. Ranulf of the Bessin, Nigel of the Cotentin, Haimo Dentatus of Creully and Grimoald of Plessis joined him.
The plot came to a head while William was hunting near Valognes, deep in hostile country. Warned at night — by a fool named Golet in Wace’s twelfth-century telling, which is the only account of the detail — he rode alone through the dark, forded the Vire at low tide, avoided Bayeux, and reached Falaise. He then did the one thing that could change the odds: he went to his overlord. Henry I of France had every reason to prefer a dependent young duke to a strong confederacy on his border, and brought the royal army into Normandy.
The two forces met in the treeless rolling country between the Orne and the Muance, near the villages of Bellengreville and Conteville. The fighting was a cavalry affair, decided in a series of charges rather than by manoeuvre: the sources describe individual encounters, not lines. Haimo Dentatus unhorsed the king and was killed by the royal household; William is credited with unseating a Cotentin knight in the first shock.
Two things decided it. Ralph Tesson of Thury, who had sworn with the rebels, changed sides before the engagement — by Wace’s account he kept his oath to strike William by tapping him with his glove, which is the kind of story that survives because it is memorable rather than because it is documented. And the rebel leaders never fought as one body: Guy’s contingent held longest, the others broke, and the retreat westward funnelled into the Orne crossings where the mills at Borbillon are said to have choked with bodies.
William did not exterminate the beaten. Nigel of the Cotentin was eventually reconciled and kept his viscounty; the confiscations were real but limited. Guy of Burgundy shut himself in Brionne, which William besieged — the accounts differ on whether for months or three years — with siege castles on both banks of the Risle until it surrendered; Guy was allowed to leave for Burgundy.
The more lasting instrument was the Truce of God proclaimed at the council of Caen in 1047, under the duke’s authority as much as the church’s. It banned private war from Wednesday evening to Monday morning and protected clergy, churches and the unarmed, and William’s enforcement of it made ducal peace a matter of ducal power rather than pious hope. The pattern of his later rule — legality asserted loudly, force applied without hesitation — is already visible in 1047.
The years after Val-ès-Dunes were not quiet. William took Domfront and Alençon from the count of Anjou, married Matilda of Flanders against papal objection, and then had to fight his rescuer: Henry I of France, alarmed at what he had helped create, invaded Normandy and was beaten at Mortemer in 1054 and again at Varaville in 1057.
Out of twenty years of that came the thing that mattered in 1066: a duchy whose castles were licensed, whose magnates campaigned where the duke sent them, and whose mounted retinues had spent a generation fighting together. The army that crossed the Channel to win the Battle of Hastings was built in the wars that began on the plain east of Caen.