During April 1356 the French took control of most of Normandy and laid
siege to those fortifications which refused to surrender. The
Cotentin area in the north-west was pro-Navarrese, but the French concentrated on mopping up Navarrese strongholds in central Normandy. Charles, the dauphin, who was also the
duke of Normandy, took charge of suppressing these holdouts. The major Navarrese fortifications he focused on were
Pont-Audemer,
Breteuil,
Tillières-sur-Avre and
Évreux. The French king was at
Chartres assembling an army with which to move against the Black Prince in Gascony. An , a formal call to arms for all able-bodied males, was announced by the French on 14 May 1356. The response was unenthusiastic and the call was repeated in late May and again in early June. The king of Navarre was the
count of Évreux, and Évreux was the capital of his holdings. This caused Charles to take personal command of its siege; he ordered several assaults, which were unsuccessful. In early June another attack breached the
walls and the defenders were forced back to the
citadel, leaving the town in flames. A surrender of the citadel was negotiated, in exchange for granting the garrison, which included Navarre's senior councillors, free passage to Breteuil. The town of Pont-Audemer was attacked by a French force commanded by
Robert de Houdetot; it is unclear if the town was taken, as with Évreux, but in any event the citadel held out. Houdetot ordered assaults on the citadel, which failed; so he drove
mines towards its walls in an attempt to sap them. The third Navarrese-held position in central Normandy was the walled town of Breteuil; it possessed a strong citadel, built some 300 years earlier. The town was prosperous, but as a fortification it was strategically unimportant. It was besieged by a large French force, but no siege works were undertaken against it. While this situation was developing John II felt the need to stand ready to personally intervene in Normandy if needed. He had already entered into commitments that a royal army would succour south-west France, and so he ordered a second army to be raised at
Bourges; John's third son, the fifteen-year-old
John, Count of Poitiers, was given nominal command. JohnII remained at Chartres.
Philip of Navarre, a younger brother of Charles of Navarre, took command of several adherents of his brother and withdrew to the northern Cotentin. From there he appealed to the English king for military assistance. Edward decided to back the Navarrese. He had been preparing an expedition to Brittany under
Henry, Earl of Lancaster, as part of the
War of the Breton Succession; Edward diverted this to Normandy to support the French rebels. On 18 June 1356 Lancaster arrived at
St Vaast la Hogue in the north-east Cotentin with 500
men-at-arms and 800
longbowmen. They were reinforced by 200 Normans under Philip of Navarre. The English commander
Robert Knolles joined Lancaster in
Montebourg with a further 800 men detached from English garrisons in Brittany. The historian
Clifford Rogers suggests that these 2,300 men were reinforced by up to 1,700 men from Navarrese-held fortifications during the following month.
Relief On 24 June the English set out from Montebourg, burning and looting their way through western Normandy. Lancaster's small army arrived at Pont-Audemer on the 30th. It is unclear whether the town had already been taken by the French, but the citadel was certainly close to falling, as the French had nearly succeeded in driving their mines under its walls. They fled on hearing of Lancaster's approach, abandoning their baggage and siege equipment. The English spent two days provisioning the town and filling in the French excavations. Detaching 100 men to reinforce the garrison, Lancaster marched south on 2 July, reaching Breteuil on the 5th. Its besiegers retired in good order and it was resupplied by the relieving force sufficiently to stand a siege for a year. With the English marching east, John ordered all available mobile forces to be concentrated at
Rouen to head them off. John arrived on 1 July, just before news of Lancaster's force turning south. John was forced to wait in Rouen to allow his now scattered forces to assemble. On 5 July he headed south in haste with his army, on Lancaster's trail. The English continued their march south on 4 July to
Verneuil, seized it, looted it and took prisoner anyone who it was considered might be worth a
ransom. The citadel held out until the 6th, when its defenders negotiated a surrender. The attack on Verneuil was probably motivated by the prospect of looting a rich town; no attempt was made to relieve Navarrese-held Tillières-sur-Avre, to the east. The same day Verneuil's citadel fell, reports of the approach of the French army were being received. It was much stronger than the English force, with perhaps ten times the number of men. It had moved to
Condé-sur-Iton and so was from the freshly provisioned Breteuil and only from Verneuil. On the 7th Lancaster rested his men and horses, but they did so arrayed in battle order outside Verneuil in case of a French attack. The French at Condé-sur-Iton also rested, having marched hard to get there in two days from Rouen, and John probably wished to delay briefly to allow more of his stragglers and detachments to join the army before offering battle. On the 8th the English marched west to
L'Aigle. The French army, which Rogers describes as "vastly superior ... in numbers", halted 2 or 3 miles (3 to 5 km) away. John sent
heralds to Lancaster inviting him to commit his force to a formal battle. Lancaster replied ambiguously but John, convinced that Lancaster's main reason for landing in Normandy was to seek a battle, believed an agreement had been reached and camped for the night. The English, however, broke camp during the night and set off on a long march of to
Argentan. By the time the French realised this attempting a pursuit was clearly hopeless, so the French returned to Breteuil and re-established their siege. A force was sent to Tillières-sur-Avre, which promptly capitulated. ==Second siege==