Henry of Grosmont, Earl of Derby, arrived in Gascony in August and, breaking with the previous policy of cautious advance, struck directly at the largest French concentration, at Bergerac.

[8] Although Gascony was the cause of the war, Edward was able to spare few resources for it, and previously when an English army had campaigned on the continent it had operated in northern France.

Fortifications were also constructed at transport choke points, to collect tolls and to restrict military passage; fortified towns grew up alongside all bridges and most fords over the many rivers in the region.

If they wished to remain in one place for any length of time, as was necessary to besiege a castle, then access to water transport was essential for supplies of food and fodder and desirable for such items as siege equipment.

[14][15] By 1345, after eight years of war, English-controlled territory mostly consisted of a coastal strip from Bordeaux to Bayonne, with isolated strongholds further inland.

[22] Derby was given a high degree of autonomy, for example his strategic instructions were: "si guerre soit, et a faire le bien q'il poet" (if there is war, do the best you can).

South-western France was encouraged to rely on its own resources, but as the Truce of Malestroit, signed in early 1343, was still in effect, the local lords were reluctant to spend money, and little was done.

Due to bad weather, his fleet of 151 ships was forced to shelter in Falmouth for several weeks en route, finally departing on 23 July.

The Gascons captured the large, weakly garrisoned castles of Montravel and Monbreton on the Dordogne in early June; both were taken by surprise and their seizure broke the tenuous Truce of Malestroit.

They had several significant successes, but their main effect was to tie down most of the weak French garrisons in the region and to cause them to call for reinforcements.

The few mobile French troops in the region immobilised themselves with sieges: of Casseneuil in the Agenais; Monchamp near Condom; and Montcuq, a strong but strategically insignificant castle south of Bergerac.

There was a further week's delay while the King and his council debated what to do, by which time it proved impossible to take any action with the main English army before winter.

Derby's intention was quite different, rather than continue a cautious war of sieges he was determined to strike directly at the French main force before it was fully assembled.

They would also be within reach of the French force under Henri de Montigny, Seneschal of Périgord, besieging nearby Montcuq.

The capture of the town, which had good river supply links to Bordeaux, would provide the Anglo-Gascon army with a base from which to carry the war to the French.

[44] The French, either lured from Bergerac by a ruse[45] or in the process of withdrawing from their siege of Montcuq,[46] or both, were caught on the road by the Anglo-Gascon army.

The French were routed, and a running fight took place as they fled toward the St. Madeleine suburb of Bergerac, at the south end of the bridge.

[47][49] The surviving French from the field army which had been besieging Montcuq were gathered by John, Count of Armagnac, and retreated north to Périgueux.

[50] The battle and subsequent capture of Bergerac were major victories; the plunder from the defeated French army and from sacking the town was immense.

[47] Losses among the French infantry are not recorded but were reported to have been heavy;[51] as was customary, most of the common soldiers were killed, regardless of whether they were still bearing arms.

[47] Derby's share of the ransoms and the loot was estimated at £34,000 (£42,000,000 in 2025 terms[note 3]), approximately four times the annual income from his lands.

[56] It was the first of a series of victories which would lead to Derby being called "one of the best warriors in the world" by a contemporary chronicler in Chroniques de quatres premier Valois[51] and to modern historians praising his generalship as: "[a] superb and innovative tactician" (Rogers);[57] "ris[ing] to the level of genius" (Rogers);[56] "brilliant in the extreme" (Burne);[58] "stunning" (Gribit).