Edward III's initial strategy was to form a ring of alliances against France. To this end he spent large amounts of money building up alliances, and in 1339 was able to take to the field with a huge army formed in a large part of his German and Flemish allies. However, no battle followed, and both sides retreated. The only notable event of this early period was the naval battle of Sluys (1340), won by Edward III. The huge cost of the alliances and the lack of success led to a political crisis in England in late 1340. The war next moved to Brittany, where the death of duke John III in April 1341 led to a disputed succession between John de Montfort, the younger brother of John III, and Charles of Blois, who had married the daughter of an older brother. By the end of 1341, Charles of Blois had occupied Brittany with French aid, and John de Montfort had allied with the English, who sent a series of armies into Brittany, including one led by Edward III in 1342. However, it was not until 1346 that a decisive battle was fought (Crecy). Edward III landed in Normandy, intending to march east to meet his Flemish allies. Philip of France had a much larger army in the field, and the two forces marched and countermarched for some time, before battle was forced at Crecy. Edward III was able to choose the battlefield, and from his defensive position was able to inflict a crushing defeat on the French. After the victory at Crecy, Edward marched on to besiege Calais, which fell in 1347 and became a key English base for the rest of the war. The next seven years were quiet, but the war simmered on, and in 1356, Edward the Black Prince led an army from Gascony on a raid into France. King John of France, with a larger army, seems to have been determined to force a battle, and the eventual fight came at Poitiers. The French attempted to copy the English tactics by dismounting their knights, but they did not have the missile troops required to support that tactic, and the battle ended in disaster, with the capture of King John it's most dramatic result. Edward III now found himself in a position of overwhelming advantage. In 1359-60 he attempted to bring the war to a end with one last great campaign, but the Rheims campaign had no significant result, and in 1360 the first phase of the war was ended by the Treaty of Bretigny, in which Edward III was granted full sovereignty over an expanded Gascony and the area arround Calais, in return for renouncing his claim to the French throne. The treaty was not fully implemented, and although peace was maintained for some years, the war was not over.
The next phase of the war was provoked by Charles V of France. In a dispute over taxation, two Gascon lords appealed to the king of France. According the treaties of 1360 he was no longer able to intervene, but he did so anyway, in effect repudiating the treaty, and during 1369 the war was resumed. This second period of the war went entirely the French way. They refused to give battle, and harried the English garrisons instead, slowly reducing the area under English control until all of Edward III's conquests other than Calais had been lost. This phase of the war petered out after the death of Charles V in 1380. A truce was made in 1388, which was apparently cemented by the marriage of Richard II to the daughter of Charles VI in 1396.
The war did not resume until the reign of Henry V. His father, Henry IV, had been too weak, and too often threatened by rebellions, including that of Owen Glyn Dwr, to get involved in French wars. Once again, the status of Gascony was the trigger of the war, and Henry crossed to France in 1415, beginning his campaign with the capture of Harfleur, before marching east with the intention of reaching Calais. Henry's army was small, tired, and the dreadfull autumn weather left them in a very dangerous position. The French could have afforded to led Henry's army disintegrate under the strain. Instead, they decided to fight, and Henry won his amazing victory at Agincourt, against overwhelming odds. After Agincourt, Henry moved to conquer Normandy. While he was engaged in the conquest of the duchy, the rest of France was occupied with the civil war between the Burgundians and Armagnacs. Once Henry had conquered Normandy, he was prepared offer terms, and accept the borders of the 1360 treaties along with Normandy. However, at this point his position was greatly strengthened by the murder in September 1419 of Duke John the Fearless of Burgundy by the Dauphin. This blatant act forced the Burgundian faction to ally with Henry V, who suddenly found himself in control of most of Northern France, including Paris itself. The same year saw Henry acknowledged by Charles VI as his heir. However, Henry died in 1422 as a result of dysentry contracted during the siege of Meaux, before Charles VI, and was never crowned. His son, Henry VI, was crowned King of France, and for some years of his reign, the English continued to advance under John, duke of Bedford, Henry V's brother. However, as the area under their control increased, the speed at which they could advance slowed, until in 1428 the siege of Orleans began. The English success was dependent on the support of the Burgundians, and the inability or inaction of the Dauphin. The balance of power changed in 1429, with the appearance of Joan of Arc, whose main impact was an increase in the morale of the French troops. The siege of Orleans was being carried out by far too small an army, and when Joan of Arc was able to get into the city, the revitalised defenders turned on the beseigers, who were spread very thinly around the city, and easily drove them off. Joan and her army then won a series of victories over the English, restoring the morale of the French. Joan herself was captured in March 1430, and the immediate danger passed. However, from this time support for the Burgundian faction began to drift, and they finally changed sides in 1435. England alone could not hope to win, and the next twenty years saw the war lost slowly, as town by town fell to the French, until, in 1454, the last English army in Gascony was defeated at Castillon, and only Calais remained in English hands.
How to cite this article: Rickard, J. (5 October 2000), Hundred Years War (1337-1453), http://www.historyofwar.org/articles/wars_hundredyears.html