The French force attracted praise for its splendour and the high status of many of its participants, but it made little progress as the town was well-garrisoned and had been left by Lancaster with food for a year.

Meanwhile, Edward the Black Prince, the son and heir of the English king, assembled an Anglo-Gascon army at Bergerac in south-west France.

At some point in August an unusually large mobile siege tower was pushed up to the walls of Breteuil and an assault launched.

[2] In 1346 Edward led an army across northern France, defeating the French at the Battle of Crécy and successfully laying siege to the port of Calais.

[9][10] In April 1355 Edward and his council, with the treasury in an unusually favourable financial position,[note 1] decided to launch offensives that year in both northern France and Gascony.

[19][20][21] During October and November 1355 an Anglo-Gascon force of between 5,000 and 6,000 men marched from Bordeaux 300 miles (480 km) to Narbonne and back to Gascony.

"[25] The English component resumed the offensive after Christmas to great effect and more than 50 French-held towns or fortifications in south-west France were captured during the following four months.

The historian Jonathan Sumption describes the French national administration as "fall[ing] apart in jealous acrimony and recrimination".

[40] 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.

[40][42] The third Navarrese-held position in central Normandy was the walled town of Breteuil; it possessed a strong citadel, built some 300 years earlier.

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.

[34] On 18 June 1356 Lancaster arrived at St Vaast la Hogue in the north-east Cotentin[36] with 500 men-at-arms[note 3] and 800 longbowmen.

[51][note 5] The attack on Verneuil was probably motivated by the prospect of looting a rich town;[44] no attempt was made to relieve Navarrese-held Tillières-sur-Avre, 7 miles (11 km) to the east.

[55] 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.

The royal army attracted great contemporary praise for its splendour and the high status of many of its participants, but it made little progress, as Breteuil was well garrisoned and had been left by Lancaster with food for a year.

[62] Meanwhile, the Black Prince had assembled an Anglo-Gascon army at Bergerac and on 4 August it marched north 6,000 strong, devastating the countryside as it went.

At some point in August an unusually large belfry, or mobile siege tower, was pushed up to the walls of Breteuil and an assault launched.

[65] Despite it being clear Breteuil could be neither stormed nor starved, John felt unable to abandon the siege as this would undermine his prestige as a warrior-king.

Some time around 20 August he offered the garrison of Breteuil free passage to the Cotentin, a huge bribe and permission to take their valuables and goods, which persuaded them to vacate the town.

Large French mobile detachments immediately sent south, towards Tours on the River Loire, to rendezvous with the forces under John of Poitiers.

[69][70] Because of the unseasonable fullness of the Loire,[71] across which the French had destroyed or strongly fortified all the bridges, Lancaster was unable to effect a junction.

The French were heavily defeated by the Black Prince's smaller force and John was captured, along with most of his court and much of the nobility of France.

[74] Charles of Navarre, who was imprisoned throughout the siege of Breteuil, was released on 9 November 1357 when a group of his partisans escaladed the castle where he was held, leading to further upheavals in the French government.