The battle of Morlaix was fought near the village of Lanmeur in Brittany, France, on 30 September 1342 between an Anglo-Breton army and a much larger Franco-Breton force. England, at war with France since 1337 in the Hundred Years' War, had sided with John of Montfort's faction in the Breton Civil War shortly after it broke out in 1341. The French were supporting Charles of Blois, a nephew of the French king.
A small Anglo-Breton army under William, Earl of Northampton, besieged the Breton port of Morlaix. Charles led a force several times larger than Northampton's from the town of Guingamp to relieve Morlaix. Warned of this, the English carried out a night march and prepared a defensive position just outside Lanmeur. When they sighted the English position, the French deployed into three divisions, one behind the other. The first of these, probably made up of Breton levies, advanced and was shot to pieces by the English archers using longbows, halting their advance; the attackers then broke without making contact. The second division, of French and Breton men-at-arms, attacked but their charge was halted when they fell into a camouflaged ditch in front of the English position. Presented with a large, close-range target the English archers inflicted many casualties. About 200 French cavalry made their way over the ditch and came to grips with the English men-at-arms, who were fighting on foot. This band was cut off by the English and all were killed or captured.
Northampton was concerned that the English archers were running low on arrows and that the ditch was so full of dead and wounded men and horses as to be ineffective as an obstacle. Therefore, when the third French division was seen to be preparing to attack the English withdrew into a wood to their rear. The French were unable to force their way in, so they surrounded it and besieged the English, possibly for several days. Northampton broke out with a night attack and returned to Morlaix. Charles gave up his attempt to relieve the town and retreated. This was the first major land battle of the Hundred Years' War and the tactics used foreshadowed those of both the French and the English for the rest of the 1340s.
Brittany was a province of France, but though the dukes of Brittany were vassals of the French kings they governed the duchy as independent rulers. Nevertheless, when the Hundred Years' War broke out in 1337 between France and England the Duke of Brittany, John III (r. 1312–1341), fought alongside his feudal lord the King of France, Philip VI (r. 1328–1350). John died on 30 April 1341, leaving a disputed succession: both his niece, Joan of Penthièvre, and his younger half-brother, John of Montfort, claimed the dukedom; Joan was married to Charles of Blois, a well-connected and militarily oriented French nobleman who was also a nephew of the King of France. John had the stronger legal claim, but the aristocracy and clergy knew little about him and mostly preferred Charles' claim. What support John had came largely from the lower levels of society, especially in the towns.
Starting in early June 1341 John seized almost all of the fortified places in Brittany and by mid-August had all but made good his claim to the duchy. Philip initially disregarded the situation, ignoring requests for assistance from Charles of Blois. Correctly suspecting that John was negotiating with the English, the French declared Charles the rightful heir on 7 September. Philip found the idea of having a relative as the duke attractive as it would bring the traditionally semi-autonomous province more firmly under royal control. He was willing to commit considerable military resources to achieve this and despatched an army to support Charles.
This army overran all of eastern Brittany, apart from Rennes, in the six months from September 1341 and captured John. John's wife, Joanna of Flanders, was in Rennes with her two-year-old son, also named John, and the ducal treasury when news of John's capture arrived. Modern historians consider her to have been an energetic and effective leader, and she acted decisively and aggressively. She recalled the field army from western Brittany, took command and moved to Hennebont. This was a small but strongly walled town with access to the sea and from there Joanna retained control of most of western Brittany, setting up her son as the faction's figurehead and heir to his father's claim to the duchy. She despatched her senior counsellor, Amaury of Clisson, to Edward III in England with a large sum in cash to encourage English military intervention and waited on events. By the end of 1341 the Montfortist cause was being supported by Edward III as an extension of the war with France.
English reinforcements took a long time to arrive. A small English force, 234 men, arrived under Sir Walter Mauny in May 1342 and relieved the siege of Hennebont. The flow of events went against the Montfortists in the face of the huge military superiority of the French. By July Joanna had been forced back to the far west of Brittany and was besieged in the port of Brest, the only remaining fortified place held by her faction. Charles of Blois and a large army had invested the town and fourteen mercenary galleys, hired from Genoa, blockaded it from the sea. Brest was on the brink of surrender when the English arrived on 18 August. Their fleet of 260 ships, including an unknown number of galleys, took the Genoese by surprise. The Genoese fled and 11 of their ships were burnt.
The English ships carried 1,350 men, a force far smaller than that of the French besieging Brest. However, seeing so many English ships crowded into the Brest Roads and the English vanguard disembarking onto the beach, the French anticipated an attack by a vast host. Charles promptly broke off the siege and withdrew, abandoning western Brittany, where the populace strongly favoured the Montfort cause. Part of the French force retreated along the south coast of Brittany, but the bulk of the army accompanied him to Guingamp. Here he concentrated his forces and called up local levies. The English were commanded by William, Earl of Northampton who was reinforced by 800 men under Robert of Artois a few days after landing. He also absorbed several small English forces and an unknown number of John of Montfort's Breton partisans. Edward III was planning to follow on with a substantial force and so Northampton's first mission was to secure a port on the north coast of Brittany.
Morlaix is approximately halfway between Brest and Guingamp. It was a town with strong fortifications and a secure harbour 50 kilometres (30 mi) from Brest. Charles left it well provisioned and well garrisoned before withdrawing a further 60 kilometres (40 mi) along the north coast road. Northampton marched on Morlaix, taking over the territory to the west of it. Arriving on 3 September and finding the garrison well-prepared to stand a siege he assaulted the town. This lasted most of the day, was pressed hard, and was eventually repulsed with the English suffering many casualties. They then settled down for a regular siege. It is possible Northampton was anticipating further reinforcement by Montfortist Bretons. Charles was now aware that his force greatly outnumbered the English, although not by as much as Charles had hoped. Edward's contingent was still in England waiting for shipping to be assembled and the French mistakenly believed it would be used in northern France, probably disembarking in Picardy. An army was gathered to confront this imagined threat, including many men transferred from Brittany.
Northampton's 1,350 men are described by the historian Jonathan Sumption as being half men-at-arms and half archers; Kelly DeVries says most were archers. They were joined by the survivors of the 234-strong advance party which had arrived three months earlier – of whom 34 were men-at-arms and 200 archers – and at least one other group of English troops of 110 men. A few days after arriving they were reinforced by a further 800 men from England, whose composition is not known. The historian Andrew Ayton concludes like Sumption that the English consisted of about the same number of archers as men-at arms. The balance of the English army was made up of Bretons with variable levels of equipment, training and commitment. The total under Northampton's command has been estimated to be between 3,000 and 5,000. It is unclear how many of this force took part in the subsequent battle, as a detachment of unknown size was left to contain the garrison of Morlaix. Ayton suggests a lower figure of 1,100 English and "an indeterminate number of Bretons".