The battle of Mortemer was fought early in February 1054 between the forces of William the Bastard, Duke of Normandy and those of Henry I, King of France and Geoffrey Martel, Count of Anjou at the town of Mortemer-en-Bray located in that part of Normandy known as the Pays de Caux.
William inherited Normandy after the death of his father Robert the Devil in 1035 and had a difficult time establishing his control over the duchy. He was only seven years old and illegitimate to boot, his succession was disputed by many and it took a number of years before anything approaching order was restored in Normandy.
In this process William was supported by king Henry I of France, his notional feudal superior, however Henry's attitude to William dramatically changed in the year 1053 with the latter's marriage to Matilda of Flanders, the daughter of Baldwin, Count of Flanders thereby cementing an alliance with one of the French king's rivals. Henry appears to have fermented a revolt by one of William's own subordinates named William of Arques, which was easily suppressed by the Duke of Normandy before he sought an alliance with the Count of Anjou. Since Geoffrey Martel of Anjou had been engaged in a long territorial dispute with Normandy over control of the County of Maine had thus had his own reasons for joining the party.
Therefore in the year 1054 a combined Franco-Angevin army gathered to invade Normandy. This army was then divided into two separate forces, each moving down the opposite sides of the river Seine, which flowed from the French capital of Paris towards the Norman capital at Rouen. King Henry himself, together with the Count of Anjou, took charge of the army that was moving down the southern side of the Seine, intending to march through Mantes and and then strike through Evreux at Rouen. To the north another army led by Count Eudes, or Odo, brother of Henry I, King of France was to attack Mortemer and the Pays-de-Caux and then link up with Henry at Rouen. In this manner it was intended to crush the upstart Duke of Normandy.
Naturally Duke William raised an army to oppose the invaders and similarly divided his forces in two; he himself led the Norman army that opposed the French king, whilst his northern command was given to Roger de Mortemer and Robert of Eu, who together with Hugh de Montfort, Hugh de Gournay, William Crispin, Walter Giffard and a young William de Warenne. It appears that the Normans were in no hurry to force a battle and simply shadowed the invaders whilst waiting for an opportune moment to strike.
The Battle of Mortemer
The French army on the right bank entered Normandy by way of Neufchatel-en-Bray and then marched in and occupied the town of Mortemer-en-Bray. They were so pleased with the ease with which they had captured the town that they threw a party, and indulged in the usual rape and pillage of the district before stumbling drunkenly into bed in the early hours of the morning. They appear to have been unaware of the presence of a substantial Norman army in the vicinity and so neglected to institute the normal precautionary measures.
A little later at dawn that same morning the Norman army crept into town and set fire to many of the buildings. The French therefore awoke to find themselves in danger of being burnt alive, grabbed what they could and in the confusion tried to make their escape from the town. Unfortunately for the French and their Angevin allies, the Normans had stationed men at every escape route and simply killed or captured the scattered groups of soldiers as they attempted to leave. The French were thus seen to be "fleeing around, skulking in the woods and bushes, the dead and wounded lying amidst the smouldering ruins, on the dunghills, about the fields, and in the by-paths."
The fighting continued until three in the afternoon by which time almost all the French were killed or taken prisoners; one of the few that managed to escape being Odo, the King's brother. The Normans had a field day; as "There was no varlet, let him be ever so mean or of ever so low degree, but took some Frenchman prisoner and seized two or three horses with all their harness; nor was there a prison in all Normandy which was not full of Frenchmen."
William, Duke of Normandy was of course on the opposite bank of the Seine and is said to have thanked God "with clasped hands and tears in his eyes" when he heard the news. The tale was told that William was so happy that he was determined to send to the French the news of the battle himself. He therefore despatched a messenger by the name of Ralph de Toeni who, in the middle of the night climbed a tree overlookong the royal tents and shouted "Frenchmen! Frenchmen! arise, arise! Prepare for flight, ye sleep too long! Away, and bury your friends who have been slain at Mortemer!"
The panicked French, thus immediately struck camp and fled back the way they had come. Duke William reportedly made the decision not to pursue the French king instructing his followers to "Let him go; he has had quite enough to trouble and cross him."
The Consequences of the battle
The Franco-Angevin invasion of 1054 marked a serious threat to William the Bastard; victory at Mortemer removed the threat and although William was later forced to meet another Franco-Angevin challenge at the battle of Varaville
in 1058, it was Mortemer that secured the defacto independence of Normandy from the French monarchy. As David Douglas
was to put it, "The battle of Mortemer reflected a major crisis in Norman history, and never again was Duke William to be faced by so formidable a threat to his power
Freed from any serious external threats, Duke William was afterwards able to complete the conquest of Maine capturing Le Mans in 1063 and investing his eldest son Robert Curthose as Count of Maine. In the following year he was able to intervene in Brittany and bring that territory within the Norman sphere of influence. By this means William extended the territory and infuence of Normandy thereby placing at his disposal the resources that he would later use to good effect in his conquest of England.
Incidentally Roger de Mortemer benefitted little from the victory, as three days after the battle he released one of his prisoners named Ralph de Montdidier. (Ralph was possibly his father-in-law.) Duke William was not best pleased, and Roger was forced into exile and deprived of Mortemer-en-Bray which was then given to William de Warrene. Roger was later forgiven, although Mortemer-en-Bray was never returned to him, but his descendants were later to be as the lords of Wigmore in Shropshire and later Earls of March. William de Warenne became one of the duke's staunchest supporters and later emerged as Earl of Surrey.
The dating of the battle of Mortemer is based on the statement by Orderic Vitalis that it took place "in hieme ante quadragesima"; that is, sometime between Ash Wednesday on the 16th February and Quadragesima Sunday on the 20th February 1047.
- J.R. Planché The Conqueror and His Companions (London: Tinsley Brothers, 1874.) http://genealogy.patp.us/conq/
- History of the Norman World
- Battles of Saint Aubin (1053) and Mortemer (1054) by William of Jumieges
- David Douglas William the Conqueror (Folio, 2002)